Note: Descriptions are shown in the official language in which they were submitted.
08936670CA
WELDLESS SAMPLE PORT
TECHNICAL FIELD
[0001] The present disclosure relates to sample ports, and in
particular to a
weldless sample port for extracting a sample from a fluid contained in a
conduit, such
as a pipe, stack or cylinder.
BACKGROUND
[0002] In many combustion processes, components of exhaust emissions
are
monitored to ensure optimum equipment performance or regulatory compliance.
Monitoring of the exhaust emissions is generally performed via one or more
exhaust
sample ports located on the periphery of an exhaust stack to extract a sample
from
the exhaust stack which can then be analyzed using chemical, optical or some
other
means to determine the constituents of the exhaust emissions.
[0003] FIG. 1 shows an industrial engine 50 connected to an exhaust
stack 52
with a prior art sample port 54 installed thereon. The engine 50 reacts fuel
and oxidizer
in a combustion process and expels the combustion gases into the exhaust stack
52,
which in turn directs the combustion gases to the atmosphere. To facilitate
emissions
measurement, a sample port 54 must often be retrofitted to the existing
exhaust
system at the combustion equipment's point of use (i.e. in the field).
[0004] FIG. 2 shows a detailed cross-sectional view of the prior art
sample port
54 installed on the engine exhaust stack 52. The installation of the sample
port 54
typically involves welding a pipe, tube or weld-o-let to the periphery of the
exhaust
stack 52 at joint 56, for example. A cap 58 may be placed at one end of the
sample
port 54 to prevent exhaust gases from venting to the atmosphere when the
sample
port is not in use.
[0005] Due to the presence of an open flame and the possibility of sparks
occurring during the welding process, many industrial locations prohibit
welding in
hazardous locations unless strict safety regulations and procedures are
adhered to.
The need for a welder combined with the additional safety requirements when
welding
in hazardous locations results in additional costs and production losses to
the end
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user. Further, due to high temperatures of the exhaust surface and combustion
gas,
as well as significant mechanical vibration, adhesive attachment of sample
ports to
the exhaust stack is typically unacceptable.
[0006] Accordingly, an additional, alternative, or improved sample
port remains
highly desirable.
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SUMMARY
[0007] One embodiment of the present disclosure is a weldless sample
port
assembly for extracting a sample from a fluid carried by a conduit, the
weldless
sample port comprising: a sample tube inserted through two holes in the
conduit, the
sample tube arranged perpendicular to a direction of fluid flow and configured
to
receive a sample of fluid; a first assembly coupled to the sample tube at a
first end of
the sample tube outside of the conduit, the first assembly providing a
compressively
sealed interface with a first hole of the two holes in the conduit; and a
second
assembly coupled to the sample tube at a second end of the sample tube outside
of
the conduit, the second assembly providing a compressively sealed interface
with a
second hole of the two holes in the conduit.
[0008] Another embodiment of the present disclosure is a method for
installing
a sample port assembly, comprising: inserting a sample tube through two holes
in a
conduit, the sample tube arranged perpendicular to a direction of fluid flow
and
configured to receive a sample of fluid; arranging a first assembly and a
second
assembly at respective ends of the sample tube outside of the conduit, at
least one of
the first assembly and the second assembly comprising a compressive body;
securing
a first fitting to the sample tube, the first fitting interfacing with the
first assembly at a
distal end of the first assembly with reference to the conduit; applying a
compressive
force to the first assembly and the second assembly; and once a pre-set load
is
achieved in the compressive body, securing a second fitting to the sample
tube, the
second fitting interfacing with the second assembly at a distal end of the
second
assembly with reference to the conduit.
[0009] Other aspects and features will become apparent to those
ordinarily
skilled in the art upon review of the following description of specific
embodiments of
the disclosure in conjunction with the accompanying figures.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Further features and advantages of the present disclosure will
become
apparent from the following detailed description, taken in combination with
the
appended drawings, in which:
FIG. 1 shows an engine with a prior art sample port installed on its exhaust
stack;
FIG. 2 shows a detailed cross-sectional view of the prior art sample port
installed on
the engine exhaust stack;
FIG. 3 shows an engine with a sample port assembly installed on its exhaust
stack in
accordance with the teachings herein;
FIG. 4 shows a detailed view of the sample port assembly installed on the
exhaust
stack;
FIG. 5 shows a cross-sectional plan view of the sample port assembly installed
on the
exhaust stack;
FIG. 6 shows an exemplary floating assembly that may be used in the sample
port
assembly;
FIG. 7A, 7B, and 7C show an alternative floating assembly that may be used in
the
sample port assembly;
FIG. 8A and 8B show an exemplary fixed assembly that may be used in the sample
port assembly;
FIG. 9 shows an alternative packing gland assembly that may be used in the
sample
port assembly;
FIG. 10 shows an alternative packing gland assembly that may be used in the
sample
port assembly;
FIG. 11 shows an alternative packing gland assembly that may be used in the
sample
port assembly;
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FIG. 12 shows a cross-section of a sample tube that may be used in the sample
port
assembly;
FIG. 13 shows a cross-sectional plan view of an alternative sample port
assembly
installed on the exhaust stack;
FIG. 14 shows a cross-sectional plan view of an alternative sample port
assembly
installed on the exhaust stack;
FIG. 15 shows a cross-sectional plan view of a system for sampling a fluid
comprising
the sample port assembly;
FIG. 16 shows a cross-section of an alternative sample tube that may be used
in the
sample port assembly;
FIG. 17 shows a cross-section of a sample probe that may be used in the system
for
sampling a fluid; and
FIG. 18 shows a method for installing the sample port assembly.
[0011] It will be noted that throughout the appended drawings, like
features are
identified by like reference numerals.
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DETAILED DESCRIPTION
[0012] A weldless sample port assembly is provided herein that is, as
an
example, suitable for use with combustion type equipment to facilitate the
measurement of exhaust emissions. The sample port assembly may be installed on
a conduit carrying a fluid, such as an exhaust stack, without a requirement
for welding.
The sample port assembly comprises a sample tube of circular or non-circular
cross-
section that passes through two holes in the exhaust stack, where the two
holes may
be pre-existing or created at the time of installation perpendicular to the
flow in the
stack. The sample tube (or pipe) contains one or more holes or slots along the
outer
surface of the tube and located in the exhaust stream for receiving exhaust
gas
samples.
[0013] The sample port assembly further comprises first and second
assemblies located at each end of the sample tube and which respectively
provide a
sealed interface with the two holes in the exhaust stack. The first and second
assemblies also provide a seal with the sample tube and exhaust stack to
ensure that
no exhaust gas escapes to the atmosphere and that no atmospheric gas enters
the
stack. Fittings may be coupled with the sample tube to secure the respective
first and
second assemblies against the exhaust stack. At least one assembly of the
first and
second assemblies is a floating assembly that comprises a compressive body.
The
compressive body may help to compensate for expansion and contraction of the
assembly and/or sample tube, as well as misalignment in the exhaust holes to
ensure
that the first and second assemblies maintain a positive seal at all times
against the
exhaust stack and the sample tube.
[0014] The sample port design provides for standard process
connections at
each end of the sample tube to facilitate connections to sampling equipment.
The
sample port assembly may further provide accurate and consistent sample
positioning, standardization of sample port configuration between combustion
equipment of similar design, as well as support a wide range of conduit or
exhaust
stack sizes and configurations. The sampling of the fluid may be a liquid
fluid or
gaseous fluid sample.
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[0015] While reference of the sample port assembly may be made to a
potential
use with combustion equipment, a person skilled in the art will readily
appreciate that
the teachings herein may be extended to various kinds of applications without
departing from the scope of the invention. Such applications may include any
fluid
sampling or measurement from any conduit where a weldless solution may be
required or would be beneficial, including but not limited to sampling or
measurement
of fluids in a hazardous or restricted location. In the description the
exhaust stack
provides the conduit transporting the exhaust gas fluid. It should be
understood that
the use of the weldless port is possible with any rigid or semi-rigid conduit
which a
sample port can be affixed.
[0016] While reference to the sample port assembly may be made to
having a
single sample port assembly installed on an exhaust stack, a person skilled in
the art
will readily appreciate that an exhaust stack may have more than one sample
port
and that the teachings herein may be applied to such a configuration
accordingly.
[0017] Embodiments are described below, by way of example only, with
reference to Figures 3-18.
[0018] FIG. 3 shows an engine 102 with a sample port assembly 100 in
accordance with the teachings herein installed on its exhaust stack 104. As
the
sample port assembly 100 may typically be installed as a retrofit to the
engine 102 in
the field, the engine 102 may be the same or different than the engine 50
shown in
FIG. 1.
[0019] FIG. 4 shows a detailed view of the sample port assembly 100
installed
on the engine exhaust stack 104. The sample port assembly 100 may comprise a
sample tube 110 for receiving a sample from the fluid stream, and the sample
tube
110 may traverse through the exhaust stack 104 substantially perpendicular to
the
direction of fluid flow. In particular, the sample tube 110 may pass through
two exhaust
through-holes 106a and 106b made in the surface of the exhaust stack 104. The
exhaust stack 104 may be of circular, square, rectangular, or various other
cross-
sectional shapes. The two exhaust through-holes 106a and 106b may be
substantially
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longitudinally- and vertically-aligned such that the sample tube 110 may pass
through
the exhaust stack 104 orthogonally to the two exhaust through-holes 106a and
106b.
[0020] The sample port assembly 100 further comprises first and second
assemblies that interface with the respective exhaust through-holes 106a and
106b.
The assemblies are shown in FIG. 4 as comprising a floating assembly 120 and a
fixed assembly 140. The first and second assemblies may be the same or
different as
will be further described herein, but at least one of the first and second
assemblies is
a floating assembly 120. The floating assembly 120 and fixed assembly 140 are
further described with reference to FIGs. 5 thru 11.
[0021] On the distal end of the respective floating assembly 120 and fixed
assembly 140 with reference to the exhaust stack 104, the sample port assembly
100
may further comprise fittings 160 and 162 that may be used to help secure the
assemblies against the exhaust stack 104 and provide a pressure-tight
connection
against the sample tube 110 for sample collection. The fittings 160 and 162
may
include, but not be limited to: swaged fittings, threaded fittings, tapered
fittings,
compression fittings, flared fittings, and/or custom fittings. The fittings
160 and 162
may be secured to the sample tube 110 by tightening an inner nut of the
fitting, for
example. The fittings 160 and 162 may be bored-through for receiving the
sample
probe as will further be described with reference to FIG 15.
[0022] The relative position of the fittings 160 and 162 away from the hot
exhaust gases may reduce the likelihood of assembly components seizing due to
material deformation and corrosion. The fittings 160 and 162 may be the same
or
different depending on the application and installation requirements, though
in FIG. 4
the fittings 160 and 162 are shown as being slightly different. The fittings
160 and 162
may further provide a standard connection for connecting to sampling equipment
(not
shown in FIG. 4). When the sample port assembly 100 or a specific fitting is
not in
use, the fittings 160 and 162 may be sealed with a cap 168 and 170
respectively to
prevent exhaust gases from escaping to the atmosphere.
[0023] FIG. 5 shows a cross-sectional plan view of the sample port
assembly
100 installed on the exhaust stack 104. The sample port assembly 100a
corresponds
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to a sample port configuration of having one floating assembly 120 and one
fixed
assembly 140. The sample tube 110 may comprise a sample hole 112 on an outer
surface thereof for receiving a sample of the exhaust gas or other fluid. The
orientation
of the sample hole 112 may be perpendicular to the direction of fluid flow,
though is
not limited to such. For example, the sample hole 112 may be arranged parallel
to the
direction of fluid flow or at any angle relative to the direction of fluid
flow. The floating
assembly 120 may be able to compensate for expansion and contraction of the
exhaust stack 104 and/or sample tube 110, as well as misalignment in the two
exhaust
through-holes 106a and 106b. This may help to ensure that the floating and
fixed
assemblies maintain a positive seal at all times against the exhaust through-
holes
106a and 106b, as well as the sample tube 110. The fixed assembly 140 may be
static
and may not be able to compensate for expansion and contraction of the exhaust
stack 104 and/or misalignment in the two exhaust through-holes 106a and 106b.
[0024] The floating assembly 120 and the fixed assembly 140 may each
have
a first sealing structure 122 and 142 providing a first seal for interfacing
with the
respective exhaust through-holes 106a and 106b. The first sealing structure
122 and
142 may help to ensure that exhaust gas does not leak to the atmosphere
through
the exhaust through-holes 106a and 106b and that atmospheric gas does not
enter
the exhaust stack 104. The floating assembly 120 and the fixed assembly 140
may
further comprise a second sealing structure 124 and 144 providing a second
seal for
coupling the respective assemblies with the sample tube 110. The second
sealing
structure may help to ensure that atmospheric gas does not enter into the
exhaust
stream of the exhaust stack 104 and to ensure that exhaust gas does not escape
into
the atmosphere. The first and second seals may also be provided by the same
sealing
structure, that is, the first sealing structure 122 or 142 may be the same as
the second
sealing structure 124 or 144. In the exemplary embodiment shown in FIG. 5 the
first
sealing structure 142 and second sealing structure 144 of the fixed assembly
140 are
the same component of the fixed assembly 140, as will be further described
with
reference to FIG. 8, whereas the first sealing structure 122 and second
sealing
structure 124 of the floating assembly 120 are different components of the
floating
assembly 120, as will be further described with reference to FIG. 7.
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[0025] The floating assembly 120 may differ from the fixed assembly
140 in
that the floating assembly 120 may further comprise a compressive body 126,
depicted as a spring in the exemplary embodiment of FIG. 5. The compressive
body
126 may help to maintain the first seals and second seals of the floating
assembly
120 and fixed assembly 140 by providing a compressive force to the assemblies.
[0026] FIG. 6 shows a cross-section of an exemplary floating assembly
120a
that may be used in the sample port assembly 100. The floating assembly 120a
shown in FIG. 6 is shown with reference to the exhaust stack 104 and the
sample
tube 110. The floating assembly 120 of this embodiment comprises packing 602,
a
packing gland 604, and a spring 606. The spring 606 may be disposed between
the
fitting 160 and the packing gland 604, thereby providing a compressive force
that
maintains the assembly seal against the exhaust stack through-hole even in the
presence of exhaust stack vibration, misalignment of through-holes, etc.
[0027] The packing 602 in the exemplary floating structure 120a may
provide
the previously described first and second sealing structures 122 and 124 which
may
help to seal the floating assembly 120a against the exhaust through-hole and
the
sample tube 110. The packing 602 may be made of graphite, for example. The
spring
606 may provide the compressive body 126 previously described, which may help
to
maintain the first and second seals. The compressive spring 606 may comprise
one
or more of a helical spring, disc spring, bi-metallic spring, bushing, bellow,
or
diaphragm.
[0028] The floating assembly 120a may slide over the end of the sample
tube
110 starting with the packing 602. The packing gland 604 centers the packing
602
about the sample tube 110 and provides a mechanical stop for a distal end of
the
packing 602 relative to the exhaust stack 104. When a compressive force is
applied
to the distal end of the floating assembly 120a via the fitting 160, the
spring 606 may
be compressed and the force is transferred through the packing gland 604 and
packing 602 to the outer surface of the exhaust stack 104.
[0029] As the packing 602 is forced into the side of the exhaust stack
104, a
seal is created between the packing 602 and the surface of the exhaust stack
104 as
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well as between the packing 602 and the inner surface of the packing gland
604. At
the same time, the compressive force also deforms the packing 602, creating a
seal
between the inner surface of packing 602 and the periphery of the sample tube
110.
Once the desired spring pre-load is achieved in spring 606, an inner nut of
the fitting
160 may be tightened securing the fitting 160 to the sample tube 110 and
securing
the floating assembly 120 in place against the exhaust stack 104. The spring
606 may
optionally be removed under conditions where there is sufficient elasticity in
the
packing 602 to maintain a positive seal at all times.
[0030] FIG. 7A, 7B, and 7C (collectively referred to as FIG. 7) show
an
alternative floating assembly 120b that may be used in the sample port
assembly 100.
In particular, FIG. 7A shows a cross-sectional side view of the alternative
floating
assembly 120b, FIG. 7B shows a full side view of the alternative floating
assembly
120b, and FIG. 7C shows the full front view of the alternative floating
assembly 120b.
[0031] In the alternative floating assembly 120b that may be seen in
FIG. 7A,
the floating assembly 120b may comprise a packing gland 702 providing the
first
sealing structure against the exhaust stack. The packing gland 702 may have a
concave surface for providing the sealed interface with the corresponding
exhaust
through-hole, for example exhaust through-hole 106a. Internal to the packing
gland
702 may be packing 704 used for providing the second sealing structure of the
floating
assembly 120b against the sample tube 110. The floating assembly 120b may
further
comprise a packing follower 706. The packing 704 may be made of graphite, for
example. The packing follower 706 may be made of stainless steel, for example.
[0032] A spring 708 may circumferentially wrap around the external
surface of
a spring guide 710, which in turn houses the packing gland 702, packing 704,
and
packing follower 706. The spring guide 710 may help to center the spring 708
about
the sample tube 110 and provides a mechanical stop for one end of the spring
708. A
spring stop 712 may provide a mechanical stop for the other end of the spring
708 as
well as interface with the fitting 160.
[0033] The floating assembly 120b may be slid over a first end of the
sample
tube 110 starting with the packing gland 702. When a compressive force is
applied to
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the spring stop 712 via the fitting 160, the spring 708 is compressed and the
force is
transferred through the spring guide 710, packing follower 706, packing 704,
and
packing gland 702 to the outer edge of the exhaust through-hole 106a in the
exhaust
stack 104. Changes in the compression of the spring 708 may help to compensate
for
the contraction and expansion and/or misalignment of the assembly during
normal
operation and ensures that a positive seal is maintained at all times.
[0034] As the concave surface of the packing gland 702 is forced into
the
exhaust through-hole 106a in the exhaust stack 104, the first seal is created
between
the exhaust through-hole 106a and the packing gland 702. The fitting 160 may
be
used to secure the floating assembly 120b in place once a desired compression
of
the spring 708 is achieved.
[0035] FIG. 8A and 8B (collectively referred to as Figure 8) show a
fixed
assembly that may be used in the sample port. In particular, FIG. 8A shows a
cross-
sectional side view of an exemplary fixed assembly 140, and FIG. 8B shows a
full
side view of the exemplary fixed assembly 140.
[0036] In the exemplary fixed assembly 140 as shown in FIG. 8A, the
fixed
assembly 140 may comprise a front ferrule 802, a back ferrule 804, and a
modified
nut 806. The front ferrule 802 may have a wedged surface or concave for being
inserted into the corresponding exhaust through-hole, for example 106b, which
provides the first sealing structure 142 described with reference to FIG. 5.
The fixed
assembly 140 may be slid over a second end of the sample tube 110 starting
with the
front ferrule 802. The inner nut of the fitting 162 may be tightened to secure
the fitting
162 to the sample tube 110. At this point, the fixed assembly 140 is still
free to move
until a compressive force is applied between the floating assembly 120 and the
fixed
assembly 140. The application of a compressive force to cause the fixed
assembly
140 to seal against the exhaust through-hole 106b and sample tube 110 will be
further
described with reference to FIG. 18, which describes a method for installing
the
sample port assembly. In response to the compressive force, the front ferrule
802 may
be wedged into the corresponding exhaust through-hole 106b to provide the
first seal
of the fixed assembly 140. The front ferrule 802 in this exemplary embodiment
also
provides the second sealing structure 144 described with reference to FIG. 5,
wherein
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the compressive force is transferred via the fitting 162, the modified nut
806, and the
back ferrule 804 so that the front ferrule 802 swages against the sample tube
110 to
provide the second seal. In an alternative scenario, instead of the ferrules
swaging
against the sample tube 110 in response to the compressive force, the front
ferrule
802 and back ferrule 804 may be pre-swaged onto the sample tube 110 before
installing the fitting 162. The front ferrule 802 and back ferrule 804 would
not be free
to move along the sample tube after swaging, however by pre-swaging the
ferrules
this may allow for a greater compression or a more controlled compression to
be
applied, thereby ensuring a proper seal of the fixed assembly.
[0037] In the foregoing exemplary embodiments, the packing 602 in the
floating
assembly 120a, the concave or wedged surface of the packing gland 702 in the
floating assembly 120b, and the wedged or concave surface of the front ferrule
802
of the fixed assembly 140 are examples of first sealing structures 122 and 142
that
help provide the sealed interface between the floating and fixed assemblies
and the
through-holes 106a and 106b of the exhaust stack 104. Similarly, the packing
602
and 704 in the respective floating assemblies 120a and 120b, and the front
ferrule
802 of the fixed assembly 140 are examples of the second sealing structures
124 and
144 that help provide the second seal between the floating and fixed
assemblies and
the sample tube 110. A person skilled in the art will readily appreciate that
several
variants of sealing structures could be implemented in the floating assembly
120 and
fixed assembly 140 without departing from the scope of this disclosure. To
provide
non-limiting examples, the concave surface of the packing gland 702 could
instead
be a wedged or tapered surface, and the wedged surface of the front ferrule
802 could
be a concave or tapered surface. Further alternative structures for providing
the first
and second seals are described with reference to FIGs. 9 thru 11 and are
referred to
as alternative packing gland assemblies. The structures of these packing gland
assemblies may be implemented for either of the floating assembly 120 and
fixed
assembly 140.
[0038] FIG. 9 shows an alternative packing gland assembly 900 that may
be used
in the sample port assembly. The packing gland assembly 900 provides for an
externally threaded tapered wedge profile 902 of the packing gland 904 which
may
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mate with internal threads in through-holes 106a or 106b in the exhaust stack
104.
With this implementation, the packing gland 904 screws into the exhaust stack
104
and the threads provide the seal between the corresponding through-hole 106a
and
106b in the exhaust stack 104. The packing 906 may provide the second sealing
structure between the packing gland assembly 900 and the sample tube.
[0039]
FIG. 10 shows an alternative packing gland assembly 1000 that may be
used in the sample port assembly. The packing gland assembly 1000 provides for
a
flat profile of packing gland 1004 to interface with the exhaust through-hole
and
provide a seal there-between. With this implementation, the areas immediately
surrounding the through-holes in exhaust stack 104 may be spot faced or
counter-
bored and a flat gasket 1002 may be inserted between the flat profile of the
packing
gland assembly 1000 and the spot faced or counter- bored surface of the
exhaust
stack 104 to provide the required seal. The packing 1006 may provide the
second
sealing structure between the packing gland assembly 1000 and the sample tube.
[0040] FIG. 11 shows an alternative packing gland assembly 1100 that may be
used in the sample port assembly. The packing gland assembly 1100 provides for
the
use of an externally threaded parallel profile 1102 of the packing gland 1104
and an
0-ring gasket 1106, or flat gasket or other sealing or similar seal, to
interface with the
exhaust through-hole and provide a seal. With this implementation, the areas
immediately surrounding the through-holes in the exhaust stack 104 are spot
faced
or counter-bored and the 0-ring 1106 is inserted between the flat profile of
the packing
gland assembly 1100 and the spot faced or counter-bored surface of the exhaust
stack 104 to provide the required seal. The packing 1108 may provide the
second
sealing structure between the packing gland assembly 1100 and the sample tube.
[0041] A yet further option (not shown), provides for a saddle profile that
fits the
contour of the exhaust stack 104. A contoured flat gasket may be used to
provide the
seal between the saddle and the exhaust stack 104.
[0042] A
person skilled in the art will readily appreciate that the configurations
and sealing structures described above are exemplary in nature and that many
other
sealing structures could be used to provide the seal between floating and/or
fixed
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assemblies 120 and 140 with the sample tube and the corresponding through-hole
in
the exhaust stack 104 without departing from the scope of this disclosure.
[0043] FIG. 12 shows a cross-section of a sample tube 110 that may be
used
in the sample port assembly 100. As described with reference to FIG. 5, the
sample
tube 110 may comprise a sample hole 112 along the outer surface of the sample
tube
110 and configured to receive the exhaust gas or fluid to be sampled. The
orientation
of the sample hole 112 relative to the exhaust flow and the positioning of
each hole
along the along the length of the sample tube 110a may vary as required by the
sample technique.
[0044] FIG. 13 shows a cross-sectional plan view of an alternative sample
port
assembly 100b installed on the exhaust stack 104. The sample port assembly
100b
corresponds to the sample port configuration of having both the first and
second
assembly being floating assemblies 120, shown as floating assemblies 1302 and
1304 in FIG. 13. The first and second floating assembly may be the same or
different,
and are shown as being the same in FIG. 13. The first and second floating
assemblies
1302 and 1304 may be any of the floating assemblies as previously described,
though
are exemplary shown as floating assembly 120b described with reference to FIG.
7.
The fittings 160 on distal ends of the respective floating assemblies 120 may
also be
the same or different, though are shown as being the same in FIG. 13.
[0045] The sample port assembly 100b with this arrangement of using two
floating assemblies 120 may provide for additional flexibility and tolerance
to
compensate for the contraction and expansion and/or misalignment of the
assembly
during normal operation and to ensure that a positive seal is maintained at
all times,
as compared to just using a single floating assembly 120 and a fixed assembly
140.
.. Due to the increased flexibility, the use of two floating assemblies 120
may require
compensation for spring deflection when positioning the sample hole 112 in the
exhaust stream.
[0046] FIG. 14 shows a cross-sectional plan view of an alternative
sample port
assembly 100c installed on the exhaust stack 104. The sample port 100c is
similar to
the sample port 100b shown in FIG. 13 in that it comprises two floating
assemblies
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1402 and 1404, however a threaded sample tube 110b is shown as being used
instead of the traditional sample tube 110, and instead of fittings 160 or 162
that have
been previously described as swaged fittings, threaded nuts 164 are used to
secure
against the sample tube and hold the floating assemblies 120 in place along an
axial
location of the threaded sample tube 110b. Thus, in this exemplary embodiment
the
position of the threaded sample tube 110b, the sampling location, and spring
or
compressive body pre-load may be altered by adjusting the relative positions
of the
threaded nuts 164. This sample port assembly 100c may help to facilitate the
removal
of the sample port assembly for inspection and allows for future adjustment of
the
.. spring pre-load to compensate for changes in the spring force over time.
While fittings
are not depicted in FIG. 14 to allow a connection to sampling equipment as
will be
described with reference to FIG. 15, it will be readily apparent to a person
skilled in
the art how a threaded fitting or the like may be implemented to allow for
such a
connection.
[0047] The sample port assemblies100a-100c described herein are exemplary
in nature and are shown to depict possible configurations and variations of
the sample
port assembly 100. A person skilled in the art will readily appreciate that
sample port
assemblies having different configurations may be used without departing from
the
scope of this disclosure.
[0048] FIG. 15 shows a cross-sectional plan view of a system for sampling a
fluid comprising the sample port assembly 100d. The sample port assembly 100d
comprises two floating assemblies 1502 and 1504 similar to sample port
assembly
100b, however an alternative sample tube 110c is shown which may comprise a
sample slot 114 as opposed to a sample hole 112. A sample probe 200 comprising
a
.. sample probe tube 202 with a sample probe hole 204 thereon may be inserted
into
one of the floating assemblies as shown. This configuration may allow for
stack
traversing, wherein the sample probe hole 204 may be moved over the sample
slot
114 to receive the sample at different radial positions in the exhaust stack
104. A
fitting 166 may be provided adjacent to the floating assembly 120 for which
the sample
probe 200 is inserted through. The fitting 166 may be similar to the fittings
160 or 162
such that an inner nut may allow for the fitting 166 to be tightened against
the sample
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tube 110c, however the fitting 166 may include an outer nut or an outer
connection
without a cap 168 and which allows for the fitting 166 to provide a seal and
be coupled
with the sample probe 200. For example, the outer nut of fitting 166 may
comprise a
ductile ferrule, and when the sample probe 200 is in the desired position the
outer nut
of fitting 166 may be tightened against the sample probe 200 to provide a seal
and
secure the fitting 166 to the sample probe. The use of a ductile ferrule in
fitting 166
may facilitate repositioning of the sample probe 200, though this represents
just one
embodiment and the scope of the invention is not limited to such.
[0049] While the alternative sample tube 110c and the sample probe 200
are
shown in FIG. 15 as being used with the sample port assembly 100d, which
comprises
two floating assemblies 120, it will be appreciated by a person skilled in the
art that
these elements could be used with any of the sample ports 100a-c.
[0050] FIG. 16 shows a cross-section of the sample tube 110c that may
be
used in the sample port assembly 100. As described with reference to FIG. 15,
the
sample tube 110c may comprise a sample slot 114 along the outer surface of the
sample tube 110c and configured to receive the exhaust gas or fluid to be
sampled.
Alternatively, instead of or in addition to a sample slot 114, a plurality of
sample holes
(not shown) may be provided along the length of the sample tube at different
locations.
Such a configuration may similarly allow for stack traversing, and in order to
align the
sample probe hole 204 with respective sample holes of the plurality of sample
holes,
an external indication of position may be required.
[0051] FIG. 17 shows a cross-section of a sample probe 200 that may be
used
in the system for sampling a fluid. As described with reference to FIG. 15,
the sample
probe 200 may comprise a sample probe tube 202 and a sample probe hole 204
located thereon which can be moved relative to the sample slot 114 (or to
different
sample holes) to collect fluid samples a different positions with the conduit.
The
sample probe hole 204 may be perpendicular to the sample probe tube's outer
surface. The sample probe 200 may further comprise rings 206a and 206b that
slide
over radial grooves 208a and 208b on the periphery of the sample probe tube
202,
and which may provide a primary high temperature seal between the sample probe
tube 202 and the inner surface of the sample tube 110c. The sample probe 200
may
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further comprise a plug 210, which may help to ensure that the sample may only
be
drawn through the sample probe hole 204. A sample probe fitting 212 may be
provided at an end of the sample probe 200 opposite the sample plug 210, which
may
be used to create a seal to prevent exhaust gases from leaking to the
atmosphere.
The sample probe fitting 212 may be include but not be limited to: swaged tube
fittings,
tapered thread fittings, or the like, and may correspond to the fitting 160,
162, or 166
on the sample port assembly 100 with which the sample probe fitting 212 mates.
[0052] Starting with the plug 210, the sample probe 200 may slide into
one end
of the sample port assembly 100, for example through the floating assembly 120
as
shown in FIG. 15 via the fitting 166. The angular position of the sample probe
hole
204 may be positioned so that it is aligned with the sample slot 114 in the
sample tube
110c. The location of the sample probe 200 may be adjusted to the desired
location,
that is, the sample probe hole 204 adjusted to be positioned over the desired
location
along the sample slot 114. Once in the correct position, the outer nut of the
fitting 166
.. may be tightened and secured to the sample probe tube 202 as previously
described
with reference to FIG. 15.
[0053] FIG. 18 shows a method 1800 for installing the sample port
assembly
100. The sample tube (for example sample tube 110) may be inserted into the
conduit
such as an exhaust stack (for example through pre-made exhaust through-holes
106a
.. and 106b) or other conduit from which the sample is to be received from
(1802). The
sample tube may be inserted substantially perpendicular to the direction of
fluid flow,
with the sample hole 112 or sample slot 114 positioned accordingly for
receiving the
sample of fluid. The first and second assemblies, as well as fittings
interfacing with
the first and second assemblies, may be slid over respective ends of the
sample tube
and positioned outside of the exhaust stack (1804). Prior to sliding the first
and second
assemblies onto the sample tube, or after one of the assemblies has been slid
over
the tube but prior to sliding the second of the assemblies over the tube, the
sample
tube 110 may be cut to an appropriate length to facilitate the assembly,
though it is
not necessary.
[0054] A first fitting may be secured with the sample tube 110 (1806). For
example, if a fixed assembly (for example fixed assembly 140) is used as the
first
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assembly and is slid over an end of the sample tube 110 until the sample tube
110
contacts the fitting 162, the fitting 162 may be tightened to secure against
the sample
tube 110 and prevent movement of the fixed assembly 140 along the sample tube
110 past the fitting 162. A compressive force may be applied to the first and
second
assemblies (1808). The compressive force causes the first and second sealing
structures of the first and second assemblies to provide a seal against the
respective
exhaust through-holes 106a and 106b, as well as sample tube 110. For example,
if
the second assembly is the floating assembly 120, the first sealing structure
may be
the packing gland 702 and the second sealing structure may be the packing 704
as
shown in FIG. 7. If the first assembly is the fixed assembly 140, the first
and second
sealing structure may be the front ferrule 802 as shown in FIG. 8. A threaded
tube,
for example, may be used to apply the compressive force for assembly of the
sample
port assembly 100, though numerous techniques for applying a compressive force
to
the first and second assemblies may be implemented without departing from the
scope of this disclosure.
[0055] At least one of the first and second assemblies comprises a
compressive body. The compressive force may continue to be applied until a pre-
set
load in the compressive body is achieved. A determination is made if the pre-
set load
is achieved (1810), for example if a spring 708 is used as a compressive body
in the
floating assembly 120 this determination may be made based on a displacement
(contraction) of the spring 708. The pre-set load may correspond to a
compressive
load at which the first and second seals of the first and second assemblies
provide a
sufficient seal to the conduit. A sufficient seal may be deemed such that the
first and
second seals of the first and second assemblies are maintained even under
worst-
case conditions for differential expansion/contraction of the exhaust stack
104 and
sample tube 110. For example, under start-up conditions, the sample tube 110
may
warm up and expand faster than the exhaust stack 104, which would in turn
reduce
the compressive force applied to the seals. The pre-set load may correspond to
a
compressive load that provides this tolerance and ensures that the first and
second
seals are maintained.
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[0056] If the pre-set load has not been achieved (NO at 1810), the
compressive
force continues to be applied (1808). If the pre-set load has been achieved
(YES at
1810), the second fitting is secured with the sample tube 110 (1812), for
example by
tightening the inner nut of the fitting 160, thereby securing the second
assembly
between the fitting 160 and the exhaust stack 104. The compressive force may
then
be removed. A cap or plug may optionally be placed on the fittings connected
to both
the first and second assemblies if sampling is not taking place, or only on
one of the
fittings if sampling is taking place and an equipment connection has been made
to
one of the fittings.
[0057] Optionally, it may be desirable to perform sampling via stack
traversing,
and the sample tube 110 may comprise a corresponding sample slot 114 to
correspond to this functionality (as shown in the sample tube 110c of Figure
16 for
example). As described with reference to FIGs. 15 thru 17, a sample probe (for
example sample probe 200) may be inserted into the sample port assembly 100
through one of the first or second assemblies (1814). The sample probe 200 may
be
appropriately aligned (1816), for example by aligning the sample probe hole
202 over
the desired location of the sample tube slot 114. The fitting of the assembly
through
which the sample probe 200 has been inserted may be tightened against the
sample
probe tube to secure the sample probe and provide a seal (1818), as described
for
example with regards to FIG. 15.
[0058] The method for installing the sample port assembly 100 as
described
above is non-limiting and exemplary in nature. A person skilled in the art
will readily
appreciate that the sample port assembly 100 may have numerous different
configurations as described herein, and accordingly the method of assembly may
vary
slightly without departing from the scope of this disclosure. In another
embodiment,
for example, the sample port assembly 100 may comprise two floating assemblies
such as the sample port assembly 100b shown in FIG. 13. There may be a need to
compensate for spring defection when securing the two floating assemblies in
place
to provide accurate positioning of the sample hole of the sample tube in the
exhaust
stream. The method 1800 may secure the first and second fittings to the sample
tube
110 after the pre-set load has been achieved (YES at 1810).
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[0059] It would be appreciated by one of ordinary skill in the art
that the system
and components shown in Figures 3-18 may include components not shown in the
drawings. For simplicity and clarity of the illustration, elements in the
figures are not
necessarily to scale, are only schematic and are non-limiting of the elements
structures. It will be apparent to persons skilled in the art that a number of
variations
and modifications can be made without departing from the scope of the
invention as
defined in the claims.
[0060] Although certain components and steps have been described, it
is
contemplated that individually described components, as well as steps, may be
combined together into fewer components or steps or the steps may be performed
sequentially, non-sequentially or concurrently. Further, although described
above as
occurring in a particular order, one of ordinary skill in the art having
regard to the
current teachings will appreciate that the particular order of certain steps
relative to
other steps may be changed. Similarly, individual components or steps may be
provided by a plurality of components or steps. One of ordinary skill in the
art having
regard to the current teachings will appreciate that the system and method
described
herein may be provided by various combinations of hardware, other than the
specific
implementations described herein as illustrative examples. Numerous additional
variations on the methods and apparatus of the various embodiments described
above will be apparent to those skilled in the art in view of the above
description.
Such variations are to be considered within the scope of the present
invention.
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