Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
PAT-00148 US01
VAPOR RELIEF STRAINER WITH CLEANER
BACKGROUND OF THE INVENTION
CROS S-RELATED APPLICATION
[0001] This application is a non-provisional utility application that
claims the benefit under 35
U.S.C. 119(e) of U.S. Provisional Patent Application No. 62/448,449 filed on
January 20, 2017,
the entirety of which is incorporated herein by reference.
1. TECHNICAL FIELD
[0002] The present disclosure relates generally to vapor cleaning in
industrial processes and
more particularly to vapor relief strainers configured to filter impurities
from vapor exposed to
fibers, fines, and other non-condensable contaminants borne from processing
lignocellulosic
material.
2. RELATED ART
[0003] Several chemical, mechanical, and biological engineering processes,
including the
production of pulp and paper from lignocellulosic material, utilize steam
vapor to facilitate
production. For example in chemical pulping, operators may introduce steam
into the chip bin to
displace entrapped air in the lignocellulosic material. A steaming vessel then
pre-heats the
lignocellulosic material to complete air displacement. The practice of
displacing entrapped air
increases the bulk density of the lignocellulosic material sent to the
chemical digester, thereby
increasing production efficiency.
[0004] In mechanical pulping, operators feed steam and lignocellulosic
material through one or
more mechanical refiners to develop and separate pulp fibers. In cellulosic
biochemical production
(e.g. the production of biofuels, bioplastics, and other products), operators
may use steam explosion
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to increase the surface area of lignocellulosic material quickly for
enzymatic, biological, or
chemical hydrolysis.
[0005] The steam that passes through the lignocellulosic material and pulp
tends to collect
fibers, fines, and other lightweight impurities that are not easily
condensable. These contaminants
can be abrasive and can contribute to premature system wear if improperly
filtered. Furthermore,
unfiltered contaminants can occlude system conduits. Partially occluded
conduits effectively
narrow the conduit diameter, which can reduce yield per unit of energy
expended. Stated
differently, partially occluded conduits can increase the amount of input
energy needed to maintain
production levels.
[0006] To avoid this problem, operators generally route process steam
through one or more
vapor relief strainers disposed throughout the production system. A vapor
relief strainer may
comprise a filter screen disposed within a chamber defined by a vessel
housing. The vapor relief
strainer generally entraps contaminants as the steam flows through the filter
screen. Cleaned steam
then flows out of the vapor relief strainer for continued use in the process.
[0007] Over time, contaminants occlude the filter screen and disrupt the
screening process. To
clean the filter screen, operators may close the outlet valve and blow steam
through one or more
blowback nozzles in the filter housing at high pressure. In this manner,
operators "blow back"
steam through the filter and into the chamber to dislodge contaminants.
Because operators close the
outlet valve, the operators increase the pressure within the vapor relief
strainer. The steam flowing
upstream through the filter screen generally has a greater pressure than the
pressure of the
contaminated steam flowing downstream. As a result, the blowback method
subjects the vapor
relief strainer to pressures that exceed the vapor relief strainer's nominal
operating capacity.
Therefore, to reduce the probability of conduit or vessel rupture, operators
tend to use the blowback
method sparingly.
[0008] Furthermore, the blowback method tends to have limited effectiveness
in cleaning the
filter screen. The filter screen tends to have a greater surface area than the
area exposed to the
blowback steam. The blowback steam typically enters the filter chamber through
a conduit that
typically functions as an outlet during normal operation. The blowback steam
may expand
generally conically from the blowback conduit; however, the area of the filter
screen that the
blowback steam encounters may be less than the total surface area of the
filter screen.
Contaminants tend to be wet and clumped together on the filter screen. As a
result, the blowback
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method ineffectively cleans the total surface area of the filter screen. That
is, the blowback method
typically creates localized contaminant-free areas on the filter screen that
are located close to the
blowback conduit along the path of the blowback steam.
[0009] Furthermore, a typical vapor relief strainer is generally not
designed to be subjected to
the blowback cleaning method for prolonged periods. The accumulated pressure
increases the risk
for a fatigue related failure of one or more components in the system.
Therefore, arranging multiple
blowback valves along the filter screen to dislodge contaminants would further
increase the risk of
system failure. .
[0010] As a result, vapor relief strainers generally do not have blowback
conduits sufficient to
clear the filter screen's total surface area. Because the blowback method only
cleans a portion of
the filter screen, the blowback method effectively reduces the area of the
filter screen capable of
filtering out new contaminants. The reduced surface area decreases the amount
of time the
contaminants take to re-occlude the functional filter screen area, thereby
encouraging more frequent
use of the blowback method. The more frequently the blowback method is used,
the greater the risk
that the vapor relief strainer basket will fail.
[0011] To attempt to address this problem, a cleaning brush as more fully
described in U.S. Pat.
No. 9,475,098, (the entirety of which is incorporated herein by reference) was
developed. The
conventional cleaning brush described engages a column. The column and brush
likewise extend
through the vapor relief strainer and move axially via a transpositive piston
assembly disposed on a
support housing. However, the cleaning brush apparatus effectively tripled the
height of the vapor
relief strainer assembly. Available space in mills can be limited. Equipment
or support structures
proximate to an existing vapor relief strainer impinge a brush apparatus's
availability as an effective
cleaning solution. The brushing solution also requires an external power
source, thereby increasing
the energy demand associated with production.
SUMMARY OF THE INVENTION
[0012] The problem of contaminant accumulation in a vapor relief vessel is
mitigated by a
vapor relief strainer cleaning assembly comprising: a dislodger assembly
comprising: a shaft having
a first axial end distally disposed from a second axial end, a dislodger
support extending outwardly
from the shaft, wherein the dislodger support engages a dislodge, a discharge
support extending
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outwardly from the shaft, wherein the discharge support engages a discharge
arm, the discharge arm
having areas defining multiple exhaust openings along a length of the
discharge arm, and a lid
assembly comprising: a turbine housing having walls, wherein the walls of the
turbine housing
define a turbine chamber, a turbine vapor inlet, a first turbine vapor outlet,
and a second turbine
vapor outlet, wherein the turbine chamber fluidly communicates with the
turbine vapor inlet, the
first turbine vapor outlet, and the second turbine vapor outlet, wherein the
second turbine vapor
outlet is configured to fluidly communicate with the multiple exhaust openings
in the discharge
arm; a turbine comprising paddles extending outwardly from a turbine hub,
wherein the first axial
end of the shaft is configured to engage the turbine hub around a center of
rotation, and wherein the
turbine is configured to be disposed in the turbine housing.
[0013] The present disclosure describes a vapor relief strainer cleaning
assembly comprising a
turbine configured to power a dislodger assembly. Exemplary vapor relief
strainer cleaning
assemblies may use an existing vapor source (e.g. a power boiler) to power the
vapor relief strainer
cleaning assembly. Operators may collect and reuse the vapor used to power the
relief strainer
cleaning assembly elsewhere in the process, thereby reducing the impact of the
exemplary vapor
relief strainer cleaning assembly as a net energy consumer in the production
system. In addition, a
portion of the excess vapor used to power the vapor relief strainer cleaning
assembly may be used
as a dislodging means, thereby avoiding the need for physical contact between
the dislodge and the
inner wall of the filter screen in certain exemplary embodiments, thereby
mitigating filter screen
fatigue and wear.
[0014] Furthermore, the use of vapor from a pre-existing source and the
ability to collect said
vapor after the vapor has been used to power a turbine may allow operators to
clean vapor relief
strainers more regularly than would otherwise be feasible with the blowback
method.
[0015] Additionally, the compact size of the exemplary vapor relief
strainer cleaning assemblies
described herein may allow operators to retrofit existing vapor relief
strainers with embodiments in
accordance with this disclosure, including in instances where equipment crowds
or surrounds an
existing vapor relief strainer.
[0016] It is contemplated that the exemplary embodiments disclosed herein
may eliminate the
need for blowback conduits and blowback cleaning methods.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing will be apparent from the following more particular
description of
exemplary embodiments of the disclosure, as illustrated in the accompanying
drawings in which
like reference characters refer to the same parts throughout the different
views. The drawings are
not necessarily to scale, with emphasis instead being placed upon illustrating
the disclosed
embodiments.
[0018] FIG. 1 is a cross-sectional exploded view of vapor relief strainer
and exemplary vapor
relief strainer cleaning assembly.
[0019] FIG. 2 is a cross-sectional view of the assembled vapor relief
strainer cleaning assembly
shown in FIG. 1.
[0020] FIG. 3 is a top down cross-sectional view of the vapor relief
strainer cleaning assembly
highlighting a turbine taken along line A¨A in FIG. 2 looking down toward the
first end of a vapor
relief strainer housing.
[0021] FIG. 4 is a top down cross-sectional view of the vapor relief
strainer cleaning assembly
taken along line B¨B in FIG. 2 looking down toward the first end of the vapor
relief strainer
housing.
[0022] FIG. 5 is a schematic diagram of a vapor relief strainer affixed to
a steaming vessel.
[0023] FIG. 6 is a schematic representation of an alternative embodiment of
the vapor relief
strainer cleaning assembly comprising a stub shaft and multiple dislodgers.
[0024] FIG. 7 is a schematic representation of an alternative embodiment of
a vapor relief
strainer cleaning assembly comprising a hollow stub shaft, hollow discharge
supports, multiple
hollow discharge arms, and multiple dislodgers.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The following detailed description of the preferred embodiments is
presented only for
illustrative and descriptive purposes and is not intended to be exhaustive or
to limit the scope and
spirit of the invention. The embodiments were selected and described to best
explain the principles
of the invention and its practical application. One of ordinary skill in the
art will recognize that
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many variations can be made to the invention disclosed in this specification
without departing from
the scope and spirit of the invention.
[0026] Corresponding reference characters indicate corresponding parts
throughout the several
views. Although the drawings represent embodiments of various features and
components
according to the present disclosure, the drawings are not necessarily to scale
and certain features
may be exaggerated in order to better illustrate embodiments of the present
disclosure, and such
exemplifications are not to be construed as limiting the scope of the present
disclosure in any
manner.
[0027] References in the specification to "one embodiment", "an
embodiment", "an exemplary
embodiment", etc., indicate that the embodiment described may include a
particular feature,
structure, or characteristic, but every embodiment may not necessarily include
the particular feature,
structure, or characteristic. Moreover, such phrases are not necessarily
referring to the same
embodiment. Further, when a particular feature, structure, or characteristic
is described in
connection with an embodiment, it is submitted that it is within the knowledge
of one skilled in the
art to affect such feature, structure, or characteristic in connection with
other embodiments whether
or not explicitly described.
[0028] Although specific terms are used in the following description for
the sake of clarity,
these terms are intended to refer only to the particular structure of the
embodiment selected for
illustration in the drawings, and are not intended to define or limit the
scope of the disclosure.
[0029] The singular forms "a," "an," and "the" include plural referents
unless the context
clearly dictates otherwise. Numerical values should be understood to include
numerical values that
are the same when reduced to the same number of significant figures and
numerical values that
differ from the stated value by less than the experimental error of
conventional measurement
technique of the type described in the present application to determine the
value.
[0030] All ranges disclosed herein are inclusive of the recited endpoint
and are independently
combinable.
[0031] As used herein, approximating language may be applied to modify any
quantitative
representation that may vary without resulting in a change in the basic
function to which it is
related. Accordingly, a value modified by a term or terms, such as "about" and
"substantially," may
not be limited to the precise values specified. The modifier "about" should
also be considered as
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disclosing the range defined by the absolute values of the two endpoints. For
example, the
expression "from about 2 to about 4" also discloses the range "from 2 to 4."
[0032] It should be noted that many of the terms used herein are relative
terms. For example,
the terms "upper" and "lower" are relative to each other in location, i.e. an
upper component is
located at a higher elevation than a lower component in a given orientation,
but these terms can
change if the device is flipped. The terms "inlet' and "outlet" are relative
to a fluid flowing through
them with respect to a given structure, e.g. a fluid flows through the inlet
into the structure and
flows through the outlet out of the structure. The terms "upstream" and
"downstream" are relative
to the direction in which a fluid flows through various components, i.e. the
flow of fluids through an
upstream component prior to flowing through the downstream component.
[0033] The terms "horizontal" and "vertical" are used to indicate direction
relative to an
absolute reference, i.e. ground level. However, these terms should not be
construed to require
structure to be absolutely parallel or absolutely perpendicular to each other.
For example, a first
vertical structure and a second vertical structure are not necessarily
parallel to each other. The
terms "top" and "bottom" or "base" are used to refer to locations/surfaces
where the top is always
higher than the bottom/base relative to an absolute reference, i.e. the
surface of the Earth. The
terms "upwards" and "downwards" are also relative to an absolute reference; an
upwards flow is
always against the gravity of the Earth.
[0034] FIG. 5 is a schematic diagram of a conventional steaming vessel and
a conventional
vapor relief strainer 501 disposed on a steaming vessel 535. During normal
operation,
contaminated vapor 580a flows from the steaming vessel 535 into a vapor relief
strainer 501
comprising a filter screen 510. The "filter screen" 510 is sometimes known as
a "filter screen
basket" by those having ordinary skill in the art. Non-condensable
contaminants 583 such as fines,
fibers, and other non-condensables flow with the contaminated vapor 580a into
the inlet 525 and
chamber 507 of the vapor relief strainer 501 and eventually accumulate on the
inner wall 579 of the
filter screen 510. The vapor 580 that passes through the filter screen 510 is
referred to as "cleaned
vapor" 580b. Over time, the accumulated non-condensable contaminants 583
occlude the filter
screen 510, thereby reducing the filtering efficacy and increasing the energy
expended to produce
the same volume of cleaned vapor 580)3.
[0035] To address this problem, operators previously used the "blowback
method" to attempt to
clean the filter screen 510. In the blowback method, operators close the
outlet valve 592 disposed
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downstream of the outlet conduit 515. The contaminated vapor 580a still flows
into the vapor relief
strainer 501, thereby allowing the pressure to increase. If the pressure
inside the system becomes
too great, the contaminated vapor 580a flows through one or more relief
conduits 596 disposed
downstream of the vapor relief strainer 501. This contaminated vapor 580a may
flow through one
or more locked open valves 591 disposed along the relief conduits 596. A
rupture pin 595 may be
disposed in one or more of the relief conduits 596. If the pressure in the
relief conduit 596 exceeds
the calibrated resistance of the rupture pin 595, the rupture pin 595 will
open, thereby allowing the
contaminated vapor 580a to flow downstream to a vent to a relief standpipe
597. Even with the
relief conduits 596 and rupture pin 595, repeated pressure accumulations
increase the risk for a
fatigue-related failure of one or more components in the system.
100361 After closing the outlet valve 592, operators pump blowback vapor
594 through
blowback conduits 518a, 518b. Further blowback conduits 518, may be disposed
downstream of the
vapor relief strainer 501. Blowback vapor 594 may come from a vapor source,
such as a power
boiler (not depicted). When the blowback vapor 594 enters the filter chamber
510, the blowback
vapor 594 may expand generally conically from the blowback conduits 518a,
518b; however, the
area of the filter screen 510 that the blowback vapor 594 encounters may be
less than the total
surface area of the filter screen 510. As a result, the blowback method
ineffectively cleans the total
surface area of the filter screen 510.
[0037] Therefore, the conventional blowback method increases the risk of
system failure and
tends to clear only the portions of the filter screen 510 aligned with an
adjacent blowback conduit
518a, 518b. To address these problems, Applicant discloses exemplary vapor
relief strainer cleaning
assemblies 100, 200 comprising dislodger assemblies (see 120, 220, 620, 720)
and a turbine (see
165, 265, 365) as more fully described herein.
[0038] FIG. 1 is an exploded view of an exemplary vapor relief strainer
cleaning assembly 100
comprising a turbine 165 and a dislodger assembly 120. A vapor relief strainer
cleaning assembly
100 may be used with processes that benefit from the re-use of cleaned vapor.
For example, in
chemical pulping, steaming vessels, chip bins, and other process vessels may
fluidly communicate
with a vapor relief strainer 101. In practice, vapor relief strainers 101 tend
to have a cylindrical
shape, but this disclosure does not prevent an exemplary vapor relief strainer
cleaning assembly 100
from having from being or generally resembling another shape.
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[0039] The vapor relief strainer 101 comprises a housing 105 having an
inner wall 188 defining
a chamber 107. A filter screen 110 may be disposed within the chamber 107. The
filter screen 110
is porous and configured to entrap non-condensable contaminants 583, FIG. 5)
such as fibers, fines,
and other non-condensables in the contaminated vapor (280., FIG. 2) by having
holes that are too
small for the non-condensable contaminants 583 to pass through. The housing
105 may further
comprise an outlet conduit 115 and one or more blowback conduits 118., 118b.
Fasteners (see 122)
may extend through a flange (not pictured) to engage a spacer 116 to a first
end 119 of the housing
105. A seal 113, such as a washer plate or other seal configured to contain
pressure within the
chamber 107 at a juncture of two or more non-fused parts may be disposed at
the first end 119 of
the housing 105. In other exemplary embodiments, the seal 113 may be disposed
in the spacer 116.
[0040] The spacer 116 may have areas defining a vapor inlet 125. It will be
appreciated that the
spacer 116 may be absent and the housing 105 may have areas defining the vapor
inlet 125 in other
exemplary embodiments. The spacer 116 may further comprise a bearing 123
configured to receive
a second axial end 134 of the shaft 133. In the depicted embodiment, the
dislodger assembly 120 is
a rotary dislodger assembly 120. However, this disclosure should not be
construed to limit the
dislodger assembly 120 to being a rotary dislodger assembly. In other
exemplary embodiments, the
dislodger assembly 120 may dislodge non-condensable contaminants 583 from the
filter screen 110
axially, diagonally, helically, with no pre-defined path, or a combination
thereof. Exemplary
dislodger assemblies 120 may be characterized by being configured to be
powered by vapor or gas
(see 290a, FIG. 2) and optionally use excess vapor or gas (see 290,, FIG. 2)
to dislodge non-
condensable contaminants 583 from the filter screen 110 or to facilitate the
dislodging of
contaminants 583 from the filter screen 110.
[0041] In the depicted embodiment, the dislodger assembly 120 comprises a
dislodger 127. The
dislodger 127 extends substantially the entire length of the filter screen
110. In other exemplary
embodiments, the dislodger 127 may comprise multiple dislodgers 127 disposed
along a length of
the filter screen 110. Dislodger supports 142 extend outwardly from a shaft
133 to support the
dislodger 127. The shaft 133 is elongate and extends through the chamber 107.
In the depicted
embodiment, the shaft 133 is hollow and comprises areas defining a shaft inlet
136, preferably near
the first axial end 138 of the shaft 133. Each dislodger support 142 engages a
spring 145. Each
spring 145 applies elastic force to the corresponding dislodger support 142
and to the dislodger 127
thereby pressing the dislodger 127 against the inner wall 179 of the filter
screen 110. A dislodger
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127 may include, by way of example, contact dislodgers such as a scraper, a
brush, a rake, a sponge,
a rag, a pipe cleaner, bristles, or other device configured to physically
contact and dislodge
contaminants 583 from the filter screen 110, non-contact dislodgers, such as
the discharge arm 129
described herein, and other devices configured to use an intermediate medium
(e.g. vapor, gas, other
fluid, or fine particles) to dislodge contaminants 583 from the filter screen
110.
100421 It will be understood that "spring" encompasses any device or
devices configured to
apply elastic force to the dislodger 127 and thereby press the dislodger 127
to the filter screen 110.
In certain exemplary embodiments, not every dislodger support 142 may engage a
spring 145. In
still other exemplary embodiments, more than one spring 145 may engage a
dislodger support 142.
In still other exemplary embodiments, dislodger supports 142 may engage more
than one dislodger
127 (see FIG. 3).
100431 Discharge supports 144 extending outwardly from the shaft 133
support a discharge arm
129. The discharge supports 144 can be hollow and may fluidly communicate with
a hollow shaft
133 and a hollow discharge arm 129. A discharge arm 129 may be hollow and
comprise areas
defining multiple exhaust openings 152 disposed along the length of the
discharge arm 129. Other
exemplary embodiments may comprise more than one discharge arm 129 (see FIG.
7). The shaft
133, discharge supports 144, and discharge arm 129 are hollow in the preferred
embodiment. The
hollow shaft 133, hollow discharge supports 144, and hollow discharge arm 129
convey a second
portion of the turbine vapor (290,, FIG. 2) from the turbine chamber 163
through the depicted
dislodger assembly 120, out through the exhaust openings 152, and through the
filter screen 110,
thereby cleaning the filter screen 110. However, it is contemplated that in
other exemplary
embodiments, the shaft 133, discharge supports 144, and discharge arm 129 may
not function as
conduits themselves, but instead support one or more external conduits fluidly
communicating with
the turbine chamber 163 and the filter screen 110.
100441 Combinations of a shaft 133, discharge support 144, or discharge arm
129 functioning as
conduits and supporting external conduits are considered to be within the
scope of this disclosure.
The discharge arm 129 may physically contact the inner wall 179 of the filter
screen 110 to
facilitate non-condensable contaminant 583 dislodgment. In other exemplary
embodiments, the
discharge arm 129 may not physically contact the inner wall 179 of the filter
screen 110 and rely on
the second portion of the turbine vapor (290,, FIG. 2) exiting the discharge
arm 129 to dislodge
non-condensable contaminants 583.
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100451 By way of example, the dislodger assembly 120 may be assembled from
stainless steel
or other material configured to endure the pressure and temperature of the
chamber 107.
[0046] A lid assembly 150 may engage a second end 111 of the housing 105,
which is distally
disposed from the first end 119 of the housing 105. The lid assembly 150 may
comprise a turbine
housing 160 and a second chamber housing 156 configured to be disposed between
the second end
111 of the housing 105 and the turbine housing 160. The second chamber housing
156 comprises a
floor 164 and shaft seal 167 for the shaft 133. Fasteners 122 may engage a cap
162 to the turbine
housing 160. The cap 162 may be disposed distally from the second chamber
housing 156.
[0047] In other exemplary embodiments, the second chamber housing 156 may
be omitted. In
embodiments in which the second chamber housing 156 is omitted, the shaft 133
may be solid and
the turbine (365, FIG. 3 and see FIG. 6) would provide the thrust to turn the
shaft 133. In the
depicted embodiment, the turbine 165 still provides thrust to turn the
dislodger assembly 120, but
the second portion of the turbine vapor (290,, FIG. 2) exiting the discharge
arm 129 (see FIG. 2)
may provide supplemental thrust. In still other exemplary embodiments, the
turbine housing 160,
second chamber housing 156, and cap 160 may be a single continuous piece. The
second chamber
housing 156 may have an area defining a second chamber 158.
[0048] The turbine housing 160 has a wall (260., FIG. 2) defining a turbine
chamber 163. A
turbine hub 159 engages the first axial end 138 of the shaft 133 with a
fastener 122 or other known
structure. Paddles (370, FIG. 3) extend outwardly from the turbine hub 159.
The turbine housing
160 further comprises a wall 260a defining a turbine vapor inlet (271, FIG.
2). A turbine vapor
inlet conduit 172 aligns with the turbine vapor inlet 271 and engages the wall
260a of the turbine
housing 160 to fluidly communicate with the turbine housing 160.
[0049] The turbine housing 160 further comprises a wall 260a defining a
first turbine vapor
outlet (273, FIG. 2). A turbine vapor outlet conduit 174 aligns with the first
turbine vapor outlet
273 and engages the wall 260a of the turbine housing 160 to fluidly
communicate with the turbine
housing 160. A throttling valve 175 may engage the turbine vapor outlet
conduit 174. Operators
may use the throttling valve 175 to regulate the flow of the first portion of
turbine vapor (290b, FIG.
2) exiting the turbine housing 160 through the first turbine vapor outlet 273.
In FIG. 1 and FIG. 2,
the turbine vapor outlet conduit 174 is disposed distally from the turbine
vapor inlet conduit 172 to
more clearly depict the profile of each conduit, however, the inlet conduit
172 and the outlet conduit
174 need not be distally oppositely disposed.
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[0050] The exemplary dislodger assembly 120, lid assembly 150, and spacer
116 may be used
to retrofit pre-existing vapor relief strainers 101. Accordingly, the turbine
vapor outlet conduit 174
and turbine vapor inlet conduit 172 may be disposed on the turbine housing 160
to accommodate
pre-existing space limitations or to optimize the length of vapor turbine
conduit. (See FIGS. 3 and
4). The compact design of the exemplary vapor relief strainer cleaning
assembly 100 comprising a
turbine 165 and a dislodger assembly 120 further permits the vapor relief
strainer cleaning assembly
100 to be used with existing vapor relief strainers 101.
[0051] The turbine housing 160 further comprises a floor 176. The floor 176
has areas defining
a second turbine vapor outlet 177. The second vapor outlet 177 permits the
turbine chamber 163 to
fluidly communicate with the second chamber housing 156 and the second chamber
158 disposed
between the turbine chamber 163 and the housing 105.
[0052] The cap 162 may comprise a sight glass 161. The sight glass 161
permits operators to
see the turbine 165 when the vapor relief strainer cleaning assembly 100 is
sealed. The cap 162
may further comprise a handle 166 to facilitate the cap's removal from the
vapor relief strainer
cleaning assembly 100 during maintenance periods. In the depicted embodiment,
fasteners 122
engage the cap 162, turbine housing 160, and second chamber housing 156 to the
second end 111 of
the housing 105. It will be understood that the lid assembly 150 may engage
the housing 105 in a
variety of ways appreciated by those skilled in the art. Each such way is
considered to be within the
scope of this disclosure.
[0053] FIG. 2 depicts the same cross-sectional view of an exemplary vapor
relief strainer
cleaning assembly 200 as in FIG. 1, except that the components are assembled
as they might be
seen in operation. In operation, contaminated vapor 280a from a process enters
a vapor inlet 225.
The contaminated vapor 280a flows into the chamber 207 and through the filter
screen 210. In this
manner, the contaminated vapor 280a may pressurize the chamber 207 to between
about 15 pounds
per square inch ("psi") to about 18 psi and may heat the chamber 207 to
between about 200 degrees
Fahrenheit (" F") to about 260 F. As the contaminated vapor 280., passes
through the porous
surface of the filter screen 210, the filter screen 210 collects contaminants
583 (FIG. 5) on the inner
wall 279 of the filter screen 210, thereby preventing the contaminants 583
from exiting the vapor
relief strainer 201 through the outlet conduit 215. Ideally, the cleaned vapor
280b exits the vapor
relief strainer 201 through the outlet conduit 215. Over time, the
contaminants 583 accumulate on
the filter screen's inner wall 279 and occlude the filter screen's pours,
thereby increasing the
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pressure and energy required to clean the contaminated vapor 280a.
Conventionally, operators
would occasionally use blowback conduits 218a, and 218b to attempt to clean
the filter screen 210,
but the blowback method generally cleans only a small portion of the filter
screen 210 near each
blowback conduit 218a, and 218b.
[0054] To address this problem, the present disclosure teaches that turbine
vapor 290a may be
pumped through the turbine vapor inlet conduit 272 and turbine vapor inlet 271
into the turbine
chamber 263. The turbine vapor 290 rotates the paddles 370 (FIG. 3), which
likewise rotate the
turbine hub 259 and the dislodger assembly 220. In this manner, the first
axial end 238 of the shaft
233 may be or may engage the turbine hub 259 around a center of rotation C.
The moving
dislodger 227 thereby dislodges non-condensable contaminants 583 from
substantially the entire
length of the filter screen 210. The non-condensable contaminants 583 may then
fall downward
into the process. For example, if the vapor relief strainer 201 were affixed
to a steaming vessel 535
the contaminants would fall back into the steaming vessel 535.
[0055] After exerting a pressing force on the paddles 370, a first portion
of turbine vapor 290b
may exit the turbine chamber 263 through the first turbine vapor outlet 273
and turbine vapor outlet
conduit 274 or through the second turbine vapor outlet 277. Operators may use
the throttling valve
275 to regulate the rate at which the first portion of the turbine vapor 290b
exits the turbine housing
260 and thereby regulate the rate at which the dislodger assembly 220 rotates.
A second portion of
turbine vapor 290, that does not exit through the throttling valve 275 may
exit the turbine chamber
263 through the second turbine vapor outlet 277. The second portion of the
turbine vapor 290,
enters the shaft inlet 236. Upon entering the shaft inlet 236, the second
portion of the turbine vapor
290, flows through the shaft 233 and downstream through the discharge supports
244 and into the
discharge arm 229. The second portion of the turbine vapor 290, then exits the
dislodger assembly
220 through the multiple exhaust openings 152 disposed along the discharge arm
229, thereby
further dislodging and cleaning out any fines or other non-condensable
contaminants 583 that may
have become lodged within the openings of the filter screen 210.
[0056] The discharge supports 244 disposed further from the turbine housing
260 may have a
greater width than discharge ports 244 disposed nearer to the turbine housing
260. The increasing
intervals may permit uniform flow of turbine vapor 290 into the discharge arm
229 as the turbine
vapor 290 loses pressure.
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[0057] The second portion of the turbine vapor 290, is also cleaned upon
passing through the
filter screen 210 and may exit the vapor relief strainer 201 through the
outlet conduit 215. For this
reason, the turbine vapor 290 may comprise contaminated vapor 280a in certain
exemplary
embodiments. In other exemplary embodiments, the turbine vapor 290 may be
substantially clean.
It is preferred to use clean vapor, however, because using contaminated vapor
will likely clog the
system over time.
[0058] One feature of the exemplary embodiments comprising discharge arm
229 is that the
second portion of the turbine vapor 290, passes through the filter screen 210
and may carry or force
through an amount of non-condensable contaminates 583 through the filter
screen 210. However,
when used in conjunction with a dislodger 227, the dislodger assembly 220 may
clean the inner wall
279 of the filter screen 210 while pushing some contaminants through the
filter screen 210 thereby
causing the non-condensable contaminants 583 lodged in the filter screen 210
to improve the
filtering qualities of the vapor relief strainer 200, while preventing
excessive accumulation of non-
condensable contaminants 583 on the inner wall 279 of the filter screen 210.
In this manner,
exemplary vapor relief strainer cleaning assemblies 200 may maintain optimal
filtration conditions
and avoid an excessive accumulation of non-condensable contaminants 583 on the
inner wall 279 of
the filter screen 210 that would otherwise render the vapor relief strainer
201 less functional or non-
functional.
[0059] To assist in the movement of a portion of the non-condensable
contaminants 583 through
the filter screen 210, the filter screen holes may have curved inlets on the
inner wall 279 of the filter
screen 210 such as the curved inlets described in U.S. Pat. No. 7,799,173, the
entirety of which is
incorporated herein by reference.
[0060] FIG. 3 is a top-down view of an exemplary vapor relief strainer 300.
Turbine vapor
390a may enter the turbine vapor inlet conduit 372 and thereby enter the
turbine chamber 363. The
incoming turbine vapor 390 presses on the paddles 370 and thereby rotates the
turbine 365. The
turbine vapor inlet conduit 372 is desirably disposed at angle relative to the
inner sidewall 389 of
the turbine housing 360. This angle facilitates turbine 365 rotation.
[0061] The turbine vapor outlet conduit 374 may also be disposed at an
angle relative to the
inner sidewall 389 of the turbine housing 360. FIG. 3 more clearly depicts a
first portion of the
turbine vapor 390h exiting the turbine chamber 363 through the first turbine
vapor outlet 373 and
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turbine vapor outlet conduit 374. A second portion of the turbine vapor 390,
exits the turbine
chamber 363 through the second turbine vapor outlet 377.
[0062] The turbine vapor 390a may come from an existing source (e.g.
typically a power boiler),
thereby obviating the need for an additional power source. Using turbine vapor
390a from an
existing source may eliminate or significantly reduce the need for additional
energy to clean the
vapor relief strainer 401 (FIG. 4). Because the vapor required to rotate the
turbine 365 is minimal
compared to the needs of a mill (e.g. a pulp mill), and because operators can
collect and reuse the
clean first portion of the turbine vapor 390b from the turbine vapor outlet
conduit 374, the
exemplary vapor relief strainer cleaning assemblies 300 disclosed herein may
be run constantly if
desired, thereby maintaining or improving the original efficiency of a vapor
relief strainer 301 over
greater periods of time than were previously possible using conventional
methods.
[0063] FIG. 4 is a cross-sectional view of the vapor relief strainer
cleaning assembly 100
comprising a turbine 365 (shown in FIG. 3) and a dislodger assembly 420. FIG.
4 is taken along
line B¨B in FIG. 2 looking down toward the first end 219 of the vapor relief
strainer housing 405.
The second portion of the turbine vapor 490, flows down through the shaft 433
and outwardly
through discharge supports 444 and discharge arm 429. As the second portion of
the turbine vapor
490, exits the discharge arm 429 and flows through the filter screen 410, the
second portion of the
turbine vapor 490, may facilitate the cleaning of the inner wall 479 of the
filter screen 410.
[0064] If the turbine vapor 390a flows as depicted in FIG. 3, the dislodger
assembly 420 will
rotate around the center of rotation C in a counter clockwise direction R. It
will be understood that
the exemplary vapor relief strainer cleaning assembly (see 100, 200; FIG. 1
and FIG. 2) may be
configured to rotate in either direction. As the dislodger assembly 420
rotates, springs 445 disposed
in a dislodger support 442 press the dislodger 427 against the inner wall 479
of the filter screen 420.
The movement of the dislodger 427 against the filter screen 410 dislodges
accumulated non-
condensable contaminants 583 and thereby cleans the filter screen 410 using
turbine vapor 390
(FIG. 3). A blowback conduit 418b and an outlet conduit 415 are depicted for
reference.
[0065] FIG. 6 is a schematic representation of an alternative embodiment of
a dislodger
assembly 620 of an exemplary vapor relief strainer cleaning assembly 200. In
FIG. 6, the dislodger
assembly 620 comprises multiple dislodgers 627a, 627b. The shaft 633 is a
solid stub shaft 633 that
does not extend through the length of the chamber 107; rather, the first
portion of the shaft 633'
extending into the turbine chamber 363 and terminating in a first axial end
238 (see FIG. 2)
CA 2992479 2018-01-19
PAT-00148 US01
comprises the turbine hub 259 and the distal portion of the shaft 633"
terminating in a second axial
end 634 and engages distally disposed dislodger supports 642a, 642b. Each
dislodger support 642a,
642b engages a respective dislodger 627a, 627b. The turbine 365 and turbine
vapor 390 rotate the
exemplary dislodger assembly 620 having multiple dislodgers 627a, 627b to
clean the inner wall 279
of the filter screen 210. In other exemplary embodiments, the dislodgers 627a,
627b may be non-
contact dislodgers such as a discharge arm 729, or other devices configured to
use an intermediate
medium (e.g. vapor, gas, other fluid, or fine particles) to dislodge
contaminants 583 from the filter
screen 210 assembly.
[0066]
FIG. 7 is a schematic representation of an alternative embodiment of a
dislodger
assembly 720 of a vapor relief strainer cleaning assembly 200. In the depicted
embodiment, the
dislodger assembly 720 comprises a hollow stub shaft 733, multiple hollow
discharge arms 729a,
729b and a hollow discharge support 744a, 744b engaging a respective hollow
discharge arm 729a,
729b, wherein the dislodger assembly 720 comprises multiple dislodgers 727a,
727b. Each dislodger
support 742a, 742b engages a respective dislodger 727a, 727b. The depicted
embodiment operates
as disclosed with reference to FIGS. 1 and 2. The turbine 365 and turbine
vapor 390 provide the
motive force to rotate the exemplary dislodger assembly 720 to clean the inner
wall 279 of the filter
screen 210. Furthermore, the second portion of the turbine vapor '790, may
provide additional
motive force to the dislodger assembly 720 and may further dislodge
contaminants that have
accumulated on the inner wall 279 of the filter screen 210. As represented in
FIG. 7, the multiple
exhaust openings 752 in a discharge arm 729 may become wider or more elongate
(or both wider
and more elongate) as the exhaust openings 752' are disposed further from the
turbine 365. Larger
exhaust openings 752' disposed further from the turbine 365 may permit the
second portion of the
turbine vapor 790, exiting the exhaust openings 752' to pass through the
filter screen 210 at a
substantially uniform rate and pressure and thereby facilitate dislodging
contaminants and cleaning
the inner wall 279 of the filter screen 210 evenly along the length of the
filter screen 210. It will be
appreciated that although multiple exhaust openings 752, 752' are considered
to comprise the
preferred embodiment, a single exhaust opening 752, 752' in a discharge arm
729 is considered to
be within the scope of this disclosure. The exhaust openings 752, 752' may
face the inner wall 279
of the filter screen 210. In other exemplary embodiments, the exhaust openings
752, 752' may be
disposed at an angle relative to a radial line extending from the center of
rotation C. Exhaust
openings 752, 752' disposed at an angle may facilitate the movement of the
discharge arm 729
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around the center of rotation C. Without being bounded by theory, the angle of
the exhaust opening
752, 752' may facilitate dislodging contaminants 583.
[0067]
It will be understood that combinations and substitutions of the various
embodiments
disclosed herein is considered to be within the scope of this disclosure.
While this invention has
been particularly shown and described with references to exemplary embodiments
thereof, it will be
understood by those skilled in the art that various changes in form and
details may be made therein
without departing from the scope of the invention encompassed by the appended
claims.
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