U.S. patent application number 10/971185 was filed with the patent office on 2006-04-27 for optical viewing system for monitoring a wide angle area of interest exposed to high temperature.
This patent application is currently assigned to Siemens Westinghouse Power Corporation. Invention is credited to Hans-Gerd Brummel, Evangelos V. Diatzikis.
Application Number | 20060088793 10/971185 |
Document ID | / |
Family ID | 36206570 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060088793 |
Kind Code |
A1 |
Brummel; Hans-Gerd ; et
al. |
April 27, 2006 |
Optical viewing system for monitoring a wide angle area of interest
exposed to high temperature
Abstract
The present invention comprises a wide angle lens optical
viewing system for the non-destructive monitoring of a high
temperature area of interest with a confined space access, in
particular, in a gas turbine engine. A novel cooling scheme is
claimed that functions to cool the wide angle lens. Further, a
method of monitoring an annular combustor region in the gas turbine
via the optical viewing system is presented.
Inventors: |
Brummel; Hans-Gerd;
(Orlando, FL) ; Diatzikis; Evangelos V.;
(Chuluota, FL) |
Correspondence
Address: |
Siemens Corporation;Intellectual Property Department
170 Wood Avenue South
Iselin
NJ
08830
US
|
Assignee: |
Siemens Westinghouse Power
Corporation
|
Family ID: |
36206570 |
Appl. No.: |
10/971185 |
Filed: |
October 22, 2004 |
Current U.S.
Class: |
431/13 ;
431/75 |
Current CPC
Class: |
F23N 2229/20 20200101;
F23M 11/045 20130101; F23N 5/082 20130101 |
Class at
Publication: |
431/013 ;
431/075 |
International
Class: |
F23N 5/08 20060101
F23N005/08 |
Claims
1. An optical viewing system for the non-destructive monitoring of
a high temperature area of interest with a confined space access,
comprising: an IR imaging device; an optical probe, having a shaft,
a wide angle IR objective lens, and a relay optics unit; a cooling
system adapted to cool the wide angle IR objective lens; and a
processor that converts a detected image to a digital signal and
display the digital signal on a visual monitor.
2. The viewing system as claimed in claim 1, wherein the high
temperature, closed area of interest is a combustion chamber.
3. The viewing system as claimed in claim 2, wherein a plurality of
viewing systems are used to view a plurality of combustion
chambers, the plurality of combustion chambers arranged annularly
on a combustion turbine.
4. The viewing system as claimed in claim 1, wherein the optical
probe is located in a port in a turbine having a cylinder.
5. The viewing system as claimed in claim 1, wherein the wide angle
IR objective lens is cooled.
6. The viewing system as claimed in claim 1, wherein the wide angle
IR objective lens is cooled with cooling flow from a compressor
connected to the turbine.
7. The viewing system as claimed in claim 1, further comprising a
plurality of relay optical units arranged within the optical
probe.
8. The viewing system as claimed in claim 1, wherein the IR viewing
device is an IR camera.
9. The viewing system as claimed in claim 1, wherein the
integration time is greater than 3 micro-seconds.
10. The viewing system as claimed in claim 8, wherein the IR camera
operates with a frequency in the range of 0.9 .mu.m to 12
.mu.m.
11. The viewing system as claimed in claim 1, wherein the wide
angle IR objective lens is made of germanium.
12. The viewing system as claimed in claim 1, wherein the wide
angle IR objective lens is made from a material selected from the
group consisting of germanium, barium fluoride, zinc selinide, and
the like.
13. The viewing system as claimed in claim 2, wherein the wide
angle IR objective lens is coated with a material having a
frequency that matches the operating frequency of the IR
camera.
14. An optical probe for monitoring an annular combustion chamber
within the turbine, comprising: a shaft having a first end and a
second end; a wide angle IR objective lens arranged towards the
first end of the shaft; and a cooling hole arranged toward the
first end of the shaft and adjacent to the wide angle IR objective
lens to provide cooling air to the wide angle IR objective
lens.
15. The probe as claimed in claim 14, further comprising a relay
optics unit.
16. The probe as claimed in claim 14, wherein the shaft is made of
stainless steel.
17. The probe as claimed in claim 14, wherein the shaft has a
cooling port for cooling air to enter.
18. The probe as claimed in claim 14, wherein the shaft is adapted
to allow cooling air to enter through a plurality of cooling
ports.
19. The probe as claimed in claim 14, wherein a plurality of
cooling holes provide cooling air to the wide angle IR objective
lens.
20. The probe as claimed in claim 19, wherein the cooling holes are
evenly spaced relative to the wide angle IR objective lens.
21. The probe as claimed in claim 19, wherein the cooling hole
geometry is selected from the set of cooling hole geometries
consisting of a shaped hole, a fan shaped hole, a hole with a
diffuser, a slot, a rectangle, an ellipse, and the like, and
combinations thereof.
22. The probe as claimed in claim 19, wherein the cooling holes are
located peripherally to the wide angle IR objective lens.
23. The probe as claimed in claim 19, wherein pairs of cooling
holes are arranged peripherally to the wide angle IR objective lens
and extend radially from the center of the optical probe.
24. The probe as claimed in claim 19, wherein more than two cooling
holes are arranged peripherally to the wide angle IR objective lens
and extend radially from the center of the optical probe.
25. A method for monitoring an annular combustion chamber in an
operating turbine generator, comprising: attaching an appropriate
wide angle IR lens to a probe tip of an optical probe; installing
the optical probe in the annular combustion chamber; operating the
turbine; focusing a lens in the optical probe; capturing an image
with an IR camera; and processing the captured image.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to optical based
monitoring systems and, more particularly, to optical based
monitoring systems for monitoring a high temperature, wide angle
area of interest such as an annular combustion chamber.
BACKGROUND OF THE INVENTION
[0002] Gas turbine engines are known to include a compressor
section, a combustor section, and a turbine section. Many
components that form the turbine section, such as the stationary
vanes, rotating blades and surrounding ring segments, are directly
exposed to hot combustion gasses that can exceed 1500 C and travel
at rotational velocities approaching the speed of sound.
[0003] In some gas turbine engines, the combustion section is a
360.degree. plenum, more commonly referred to as an annular
combustor. Annular combustors typically have ceramic tiles arranged
on the inner wall of the annular combustor to insulate the
combustor cylinder from the hot, combusted gas.
[0004] However, these ceramic tiles have been known to detach from
the inner wall and can enter the flow stream, become lodged in the
first row vanes, resulting in local flow blockage. This flow
blockage may result in significant damage to turbine components
downstream of the first row vanes.
[0005] In the past, inspection for damage to turbine components has
been performed by partially disassembling the gas turbine engine
and performing visual inspections on individual components.
Alternatively, in-situ visual inspections may be performed without
engine disassembly by using a borescope inserted into a gas turbine
engine, but such procedures are labor intensive, time consuming,
costly, and require that the gas turbine engine be shut down.
[0006] It is known to inspect for turbine component damage while
the gas turbine is operating. Also, several methods and apparatus
for detecting and locating defects in turbine components while the
turbine engine is in operation have been proposed, including
acoustic, optical and infrared. However, each of these methods and
apparatus has appreciable disadvantages.
[0007] Accordingly, there continues to be a need for improved
methods and apparatus having a wide angle field of view for the
non-destructive detection of damage to turbine components.
SUMMARY OF THE INVENTION
[0008] The present invention provides an optical viewing system for
the non-destructive monitoring of a high temperature area of
interest with a confined space access, comprising an IR imaging
device; an optical probe, having a shaft, a wide angle IR objective
lens, and a relay optics unit; a cooling system adapted to cool the
wide angle IR objective lens; and a processor that converts a
detected image to a digital signal and display the digital signal
on a visual monitor.
[0009] The present invention also provides an optical probe for
monitoring an annular combustion chamber within the turbine,
comprising: a shaft having a first end and a second end; a wide
angle IR objective lens arranged towards the first end of the
shaft; and a cooling hole arranged toward the first end of the
shaft and adjacent to the wide angle IR objective lens to provide
cooling air to the wide angle IR objective lens.
[0010] Furthermore, the present invention provides a method for
monitoring an annular combustion chamber in an operating turbine
generator, comprising attaching an appropriate wide angle IR lens
to a probe tip of an optical probe; installing the optical probe in
the annular combustion chamber; operating the turbine; focusing a
lens in the optical probe; capturing an image with an IR camera;
and processing the captured image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above-mentioned and other concepts of the present
invention will now be described with reference to the drawings of
the exemplary and preferred embodiments of the present invention.
The illustrated embodiments are intended to illustrate, but not to
limit the invention. The drawings contain the following figures, in
which like numbers refer to like parts throughout the description
and drawings and wherein:
[0012] FIG. 1 is a cross section view of a combustion section of an
exemplary gas turbine fitted with an optical viewing system of the
present invention,
[0013] FIG. 2 is a perspective view of an optical probe of the
viewing system of the present invention,
[0014] FIG. 3 is a detail view of a lens portion of the optical
probe, and
[0015] FIG. 4 is a detail view of an alternate cooling scheme for
the optical probe.
DETAILED DESCRIPTION OF THE INVENTION
Overview
[0016] The invention described herein employs several basic
concepts. For example, one concept relates a wide angle viewing
system that is cooled by active cooling for use in a high
temperature environment. Another concept relates a device and a
method for monitoring ceramic tile integrity on the inner wall of
an annular combustion chamber. Another concept relates to the
monitoring of an area of interest where wide-angle viewing of a
high temperature region through a confined access space is
needed.
[0017] It is advantageous to define the term "area of interest"
before describing the invention. "Area of interest" refers to any
region where viewing or monitoring is desired. For example, the
interface between the row 1 vane and the combustion chamber in an
annular combustor in a gas turbine would be an area of
interest.
[0018] The present invention is disclosed in context of use of a
wide-angle infrared (IR) optical viewing system within a gas
turbine engine for monitoring thermal insulating tile fixity on the
combustion chamber inner wall within an annular combustion chamber.
The principles of the present invention, however, are not limited
to use within gas turbine engines or to monitor thermal insulating
tiles in an annular combustion chamber. Other applications include
any environment requiring monitoring by viewing a wide area such as
in steam turbines, electric generators, air or gas compressors,
auxiliary power plants, and the like. Additionally, other types of
high temperature conditions that can be monitored in the context of
use within a combustion turbine with the present invention include
cracked or broken components as well as combustion flame
characteristics. One skilled in the art may find additional
applications for the apparatus, processes, systems, components,
configurations, methods and applications disclosed herein. For
example, the claimed invention has application in the field of
geology monitoring pockets exposed to high temperatures in the
earth's subsurface. Further, the claimed invention also has
application in the field of fire rescue where monitoring by viewing
a confined space in a burning, or recently burned structure is
necessary. Thus, the illustration and description of the present
invention in context of an exemplary gas turbine engine for
monitoring stability and fixity of ceramic thermal insulation tiles
on the inner wall of an annular combustion chamber is merely one
possible application of the present invention. However, the present
invention has particular applicability for use as a viewing system
for monitoring the condition of turbine components.
Components
[0019] Referring to FIG. 1, the preferred embodiment of the claimed
invention is illustrated and disclosed in the context of a wide
angle viewing system 10 adapted to monitor the condition of the
thermal insulating tiles 20 lining the inner cylinder wall 25 of
the combustion cylinder 22 in an operating gas turbine. The viewing
system 10 advantageously comprises an objective lens 36 (see FIG.
2) having a wide angle field of vision 18 allowing a portion of the
area of interest, or the entire area of interest to be viewed. The
image is transferred through an optical probe 28 to an IR imaging
device 26 that is attached toward an end of the optical probe 28.
The image detected by the IR imaging device 26 is converted to a
digital signal and transmitted to a processing system 48. The
processed image can then be viewed on a monitor using conventional
image rendering program applications or stored.
[0020] Still referring to FIG. 1, the IR imaging device 26 is
preferably an IR camera 26. The IR camera 26 preferably uses a
focal plane array sensor (e.g., an array of charged coupled
devices) to measure the emitted radiance of the entire area of the
surface to be measured. One suitable IR camera 26 is described in
pending U.S. patent application Ser. No. 09/470,123 which is
incorporated herein by reference in its entirety. Although the IR
camera 26 disclosed in Ser. No. 09/470,123 is specifically adapted
to capture a dynamic event having a short integration time (e.g.,
motion requiring an ultra fast aperture speed of a few
micro-seconds), such a short integration time is not required for
the present invention because the event to be visually monitored is
a static event (e.g., detached thermal insulating tiles 22 lodged
in the flow inlet region 17 of the row 1 vanes 16). However,
although an IR camera 26 having a short integration time is not
required for monitoring a static event, it may be beneficial to use
an IR camera having a short integration time to capture dynamic
events in other contexts of use. Furthermore, if the engine
components are hot enough to emit light (i.e., glow), non IR camera
26 operating in the visible light spectrum may be used. If an IR
camera 26 is used, it 26 preferably operates with a wavelength
ranging from 0.9 .mu.m to 12 .mu.m.
[0021] Further illustrated in FIG. 1 is a processing element 48.
The processing element 48 allows for the user to view the detected
image. In the preferred embodiment, the IR camera 26 is operatively
connected to the processing element 48 by a cable connection 50 or
other suitable connection such as telemetry or a wireless area
network. The processing element 48 further comprises a video
monitor that allows the user monitor by viewing the area of
interest 17. The processing element 48 may further enhance the
viewed image via image processing software and then display the
processed image on the video monitor.
[0022] Referring to FIG. 2, the illustrated optical probe 28 is
exemplarily arranged prior to the row 1 vane 16 and the inner
surface 25 of the combustion chamber 30 (see FIG. 1). The optical
probe 28 is advantageously comprised of a shaft 32, a wide angle
lens 36, and a relay optics unit 34. The shaft 32 has a length
sufficient to traverse the cylinder wall 22 from the outer surface
23 of the combustor cylinder 22 to the inner surface 25 of the
combustor cylinder 22 and through the thermal insulating tiles 20
to view the area of interest 17 (see FIG. 1). Although there is no
requirement that the optical probe 28 be located in the combustion
chamber 30 as illustrated, it 28 is preferrably arranged such that
the field of vision 18 can detect the area of interest 17. The
shaft 32 may be circular in cross section. Shafts 32 having
circular cross sections are low in cost and readily commercially
available. Furthermore, the shaft 32 having a circular cross
section may be inserted into a circular hole in the cylinder wall
22. However, a shaft having any cross sectional geometry such as
triangular or rectangular cross sections may be used. Additionally,
combinations of different shaft 32 cross sections may connected to
produce a single shaft 32 having different cross sections. The
shaft 32 will have sufficient wall thickness to withstand the
extreme temperatures and pressures of the environment.
Additionally, the shaft 32 should have an inner wall diameter
sufficient to provide the image to the IR camera. The shaft 32 is
preferably metallic in composition and more preferably is a
stainless steel to provide material properties sufficient to
properly function in a high temperature environment. Stainless
steel shafts 32 are preferred because they are cost effective and
readily commercially available. The shaft 32 may be coated with a
thermal insulating such as a ceramic coating material to improve
the temperature resistance of the shaft 32.
[0023] One or more cooling ports 40 are advantageously arranged on
the shaft 32 at a location that allows cooling air to enter the
shaft 32. The cooling air functions to keep the optical elements
36, 34 properly cooled. Cooling air can be supplied as bleed air
extracted from a compressor section or may be supplied from any
suitable location where cooling air can be obtained.
[0024] Still referring to FIG. 2, the optical probe 28 is further
comprised of a relay optics unit 34 having one or more lens that is
arranged internal to the shaft 32. The relay optics unit 34 aids in
transferring and focusing the image detected in the combustion
chamber 30 through the shaft 32 to the IR camera 26. As
illustrated, the optical probe 28 contains a single relay optics
unit 34. However, multiple relay optic units 34 may be installed as
required.
[0025] A wide angle IR objective lens 36 is located toward an end
of the shaft 32 opposite the end that the IR camera 26 is located.
The wide angle lens 36 allows a wide area of interest 17 to be
viewed. The wide angle lens 36 is advantageously designed with a
wide field of vision 18 or wide viewing angle 18. Typically, a wide
field of vision 18 or wide viewing angle 18 is preferably larger
than 30 degrees. However, the field of vision 18 may be less than
30 degrees. The viewing capabilities of the lens 36 are partially
effected by the field of vision 18. For example, a lens 36 having a
field of vision 18 greater than 150 degrees will not have the
imaging capabilities of a lens 36 having a field of vision 18 less
than 90 degrees. With a larger field of vision 18 is a tradeoff in
perspective, detail, and resolution.
[0026] As illustrated, the field of vision 18 is depicted as an
angle. In three dimensional space, the field of vision 18 can be
thought of as generally conical in shape with the apex of the cone
at the lens 36. The wide angle lens 36 is preferable hemispherical
in shape. A hemispherical lens 36 provides a wide field of vision
18 and is commercially readily available. However, there is no
requirement that the lens 36 be hemispherical and there may be
acceptable alternate geometries such as an ellipsoid, a
hyperboloid, and the like. As illustrated, the lens 36 is
approximately 17 millimeters in diameter. While the illustrated
embodiment of the lens 36 diameter is approximately 17 millimeters,
one skilled in the art will recognize that the diameter of the lens
36 will in part depend on the amount of available energy emitted by
the area of interest 17. Furthermore, there are other
considerations that may be used in determining lens 36 size such as
the size of the entry port for the optical probe shaft 32 and
cooling flow availability.
[0027] The lens 36 may be interchangeable with the optical probe
28. That is, depending on the application, it may be beneficial to
use a lens 36 having a more narrow field of vision 18. For example,
if the area of interest 17 to be monitored can be acceptably
monitored with a lens having a more narrow (e.g., less than 180
degrees) field of vision 18, then there is no limitation preventing
use of the lens 36. As discussed below, there are advantages to
using a lens 36 having a field of vision 18 no greater than
required for the particular context of use.
[0028] In the preferred embodiment, the IR objective lens 36 is a
germanium lens 36. A germanium lens 36 is transmissive in the
wavelength range of 0.9 .mu.M to 12 .mu.m. Other materials are
suitable, such as barium fluoride, zinc selinide, and the like.
However, as would be known by one skilled in the art, the IR
objective lens 36 can be produced from any acceptable material. The
material may also be coated 46 (see FIG. 3) to further protect the
lens 36. The coating material 46 will typically have the same
wavelength as the IR camera 26. The lens 36 may protrude into the
combustion chamber 30 provided adequate cooling can be achieved to
properly cool the lens 36.
[0029] The lens 36 must be properly cooled. If the lens 36 becomes
heated to the level that it 36 begins to become emissive, the area
of interest 17 will be unobservable.
[0030] A cooling scheme 42 for the IR objective lens 36 is
illustrated in FIG. 3. The cooling 52 air functions to keep the
temperature of the lens 36 during operation below a light emitting
level. As cooling air 52 preferably enters the shaft through the
cooling ports 40 and flows through the shaft exiting through
cooling holes 42. As illustrated, a plurality of evenly spaced
circular cooling holes 42 is located toward the circumference or
periphery of the IR objective lens 36. There is no requirement that
the cooling holes be evenly spaced or located toward the
circumference or periphery of the lens 36. The lens 36 may be
surrounded by a sufficient number of cooling holes 42 to provide
adequate cooling to the lens 36 and need not be located on the
circumference of the lens 36. A single cooling hole 42 may be a
sufficient number of cooling holes 42 to properly cool the lens 36.
If desired, more cooling holes 42 than necessary to adequately cool
the lens 36 may be used. Furthermore, there is no requirement that
the cooling hole be circular in shape. For example, the cooling
hole 42 types that may be used include a shaped cooling hole 42, a
fan shaped cooling hole 42, or a cooling hole 42 with a diffuser.
Cooling hole 42 shapes as just mentioned may provide a more
efficient cooling of the lens 36. Other cooling hole 42 geometries
such as a slot, a rectangle, an ellipse, and the like may be used
to meet the cooling requirements of the lens 36. Selection of
cooling hole 42 shape or geometry may be effected by cooling
requirements and manufacturing costs with the circular cooling hole
42 being the least expensive to manufacture. Additionally, any
combination of the mentioned geometries or hole shapes may be used
to adequately cool the lens 36. The cooling flow 52 may be directed
the lens 36 as necessary to cool the lens 36. By way of example,
the cooling flow 52 may be angled from the cooling hole 42 towards
the lens 36.
[0031] As illustrated, the lens 36 is cooled by film cooling. As
known by those skilled in the art, film cooling is a proven method
of cooling components. That is, a thin film of air is developed
between the combustion gas and the lens 36 effectively insulating
the lens 36 from the gas. The thickness and flow rate of the film
is controlled by the cooling hole 42 geometry. The cooling flow may
be in the turbulent flow regime or laminar flow regime. The
insulating effect of the film cooling may provide a temperature
difference of as much as 150 C. .degree. between the combustion gas
and the lens 36.
[0032] An alternate cooling scheme is illustrated in FIG. 4.
Cooling holes 42 are arranged in pairs 54, 56 such that the pairs
54, 56 extend radially from the center of the optical probe 32. The
hole size of each hole may be different. A benefit de rived from
such a scheme is the improved cooling of the lens 36. The cooling
flow and direction of the inner cooling holes 54 and the outer
cooling holes 56 may be advantageously adjusted to more effectively
cool the lens. The velocity of the cooling flow of the inner
cooling holes 54 is preferably greater than that of the velocity of
the cooling flow of the outer cooling holes 56. This configuration
provides a pressure differential may result directing the cooling
flow of the outer cooling holes 56 closer to the lens 36. However,
there is no requirement that the flow velocity of the inner hole 54
be greater than the cooling flow velocity of the outer hole 56. The
pairs of cooling holes 54, 56 may be located equidistance from each
other circumferentially with respect to the optical probe 32 and
lens 36. It is not required that the cooling holes 54, 56 be
located equidistance from each other. Furthermore, more than two
cooling holes 54, 56 arranged radial with respect to the optical
probe 32 may be used. Combinations of the different cooling hole
arrangements may be used as well. For example, a cooling hole
arrangement having pairs of cooling holes 54, 56 may be used with a
plurality of single cooling holes 42.
[0033] Returning to FIG. 2, the illustrated embodiment may includes
a flange 38 located on the shaft 32. The flange 38 functions to
attach the optical system to the combustion cylinder wall 22 and
provide a seal between the combustion chamber 30 and exterior to
the combustion cylinder wall 22. The flange 38 also contains a
window 44 that permits the transmitted image to travel from the
combustion chamber 30 to the IR camera 26.
Method of Assembly
[0034] Referring back to FIG. 1, components of the wide angle
viewing system 10 may be mounted or installed within the combustor
cylinder wall 22 of the gas turbine. However, other locations are
suitable, for example, stationary components such as ring segments
or stationary vanes 8 that permit wide angle viewing of turbine
components. If portions of the wide angle viewing system 10 are
located in a harsh environment (i.e. inside the combustion chamber
30), a protective casing, covering or coating advantageously is
used to protect the exposed components from the aggressive
combustion chamber 30 environment, as will be understood by those
skilled in the art.
[0035] The illustrated optical probe 28 is inserted through a port
in the combustor cylinder wall 22 and traversed through the port
into the combustion chamber 30. The optical probe 28 can be
arranged in many other locations to achieve the function of wide
angle viewing as will be understood by those skilled in the art.
The field of vision 18 into the plane can be increased by
increasing the number of optical viewing systems 10 used. For
example, by spacing an appropriate number of optical viewing
systems 10 around the circumference of the annular combustion
chamber 30, the entire combustion chamber 30 may be viewed.
[0036] The optical probe 28 is advantageously secured to the
combustor cylinder wall 22 by an optional flange 38. In the context
of use in a gas turbine, the cylinder wall 22 is a convenient
location to secure the optical probe 28 to view the area of
interest 17. The flange 38 also provides a seal between the
combustion chamber 30 conditions external to the combustor cylinder
wall 22. One skilled in the art will recognize that there are other
options available to secure the optical probe 28 in an operating
position. For example, the optical probe 28 may be welded in place,
adhesively fixed in place, screwed in place with a threaded shaft
32, magnetically fixed in place, secured using thumb screws,
combinations thereof, and the like. Furthermore, the optical probe
28 may be adjustably mounted such that the probe 28 can be extended
to possibly increase the field of view 18, or retracted to decrease
the field of view 17 or adjust the lens 36 cooling if
necessary.
Method of Operation
[0037] In operation, as illustrated, when the viewing system 10 is
initiated, the IR camera 26 detects the image captured through the
wide angle lens 36. The image is converted to a digital signal and
transmitted to the processing system 48.
[0038] The viewing system 48 advantageously interprets and
processes the transmitted image. The processed image is preferably
output in a form that can be suitably visually displayed. For
example, a visual output, such as a computer monitor advantageously
allows the data to be displayed in a real time fashion because of
the capabilities of modern central processing units. Alternatively,
the data could be stored separately and used with a suitable
program or database and analyzed at a later date. Lastly, the
output could be used and compared to other output to determine
trends in the systems being monitored.
[0039] While the preferred embodiments of the present invention
have been shown and described herein, it will be obvious that such
embodiments are provided by way of example only. Numerous
variations, changes and substitutions will occur to those of skill
in the art without departing from the invention herein. Also, one
or more aspects or features of one or more embodiments or examples
of the present invention may be used or combined with one or more
other embodiments or examples of the present invention.
Accordingly, it is intended that the invention be limited only by
the spirit and scope of the appended claims.
* * * * *