Note: Descriptions are shown in the official language in which they were submitted.
CA 02173794 1999-06-09
APPARATUS AND METHOD FOR TESTING FOR VALVE LEAKS
BY DIFFERENTIAL SIGNATURE METHOD
FIELD OF THE INVENTION
This invention relates to acoustic detection of leaks in valves carrying fluid
and more
particularly to an apparatus and method for applying hardware and software to
automate the
process of acoustic detection of leaks in such valves.
DESCRIPTION OF TITS PR10R ART
Systems for carrying gases or liquids typically cont'vn numerous valves which
are
subject to developing leaks. One method of detecting leaks in valves of such
systems, the
differential signature method, is described in the following documents
Dimmick et al, "Ultrasonic leak detection cuts valve maintenance costs," Power
Engineering, August, 1986;
AVLA"' Acoustic Ikrlve Leak Analyzer Operator's Manual, ~ 1989 Leak Detection
Services, Inc.; and
AVLA'"Acoustic I~blve Leak Analyzer Test Engineer's Guide, ~ 1989 Leak
Detection
Services, Inc.
The differential signature method works by measuring acoustic signatures
defined as
the amplitude of ultrasonic signals emanating from a test point as a function
of frequency or
of time foc a given frequency. Typically, three acoustic signatures of
amplitude as a
function of frequency are taken, one at the valve and two (called the
background signatures)
at positions on a pipe upstream and downstream from the valve. The background
signatures
are taken upstream and downstream of the valve to prevent errors due to
inaccurate human
measurements and omissions of vital data. The differences between the
signature at the
valve and the background signatures indicate the presence or absence of a leak
and its
specific severity. For a non-leaking valve, these differences should be small.
The ratios of
the signature at the valve and the upstream and downstream signatures in
decibels at the
dominant frequency, which is the frequency at which the amplitudes have peak
values,
indicate the severity of the leak. The hardware for this method has typically
included a
device for taking the acoustic signatures and plotting such signatures on
graph paper with
pens of different colors. The user has then had to manually determine the
presence and
severity of the leak on the basis of the plotted signatures.
C~~ 1~7:~ 1~~4
2
The conventional method described above has the following disadvantages.
First, it
results in a massive amount of paper. Second, as the hardware performs no
analysis of the
data, and as neither the hardware nor the plots indicate the procedures for
determining the
presence and severity of a leak, the conventional method requires extensive
training of the
user, many manhours, and countless paper plots.
SUMMARY OF TIII= INVrNTION
It is an object of the invention to provide an apparatus and method for
automating the
process of acoustic detection of leaks in valves carrying fluids.
1t is a further object of the invention to provide such an apparatus and
method while
eliminating the need to print out hard copies of the acoustic signatures.
It is a further object of the invention to provide such an apparatus and
method that
require little training for proper use.
It is a further object of the invention to provide such an apparatus and
method that
offer the advantages of elimination of bulky paper records, faster data
collection, faster and
automated repeatability confirmation, easier data manipulation and analysis,
integration of
planning, recording, analyzing, reporting, and record-keeping, ease of
upgrading and
modification by simple software changes, ease of tailoring the system to a
specific client's
needs, and reduction of training and skill requirements for data collection.
It is a further object of the invention to provide.such an apparatus and
method that
offer the advantages of digital collection, analysis and conclusion recording;
a data collection
unit and accessories including a software-controlled, hardware FFT module to
convert
transducer signals to spectra for electronic transmission to a computer; a
data collection and
in-plant analysis software module; the ability to use an office PC to develop
and maintain
databases of clients' valve systems; the ability to use a generic office PC to
develop
standardized test procedures, to permit more detailed comparison and analysis
of the
signatures, and to prepare reports with a minimum of human intervention to
maintain
historical records of individual valves in clients' plants; and to enable
survey clients to view
test data and conclusions, but not to change them.
It is a further object of the invention to provide a computer based valve
signature
recorder having a programmed function key interface which guides the user
through the
planning, testing and analysis of a valve leakage survey, to provide an
accurate and
organized apparatus for managing multi-series data on five hundred or more
valves, and to
provide a method of analyzing valves with such an apparatus, which method
automatically
handles many details of instrument operation which could fmstrate the non-
electronics
oriented operator.
~1 737 9~
To achieve these and other objects, the invention includes an apparatus
comprising
transducer means for feceiving sounds from the valve system and for converting
the sounds into
electrical signals; transform means, such as fast Fourier transform means, for
receiving the
electrical signals, for transforming the electrical signals by a transform
such as a fast Fourier
transform to produce sound signatures, and for outputting digital data
representing the sound
signatures; means for comparing at least two of the sound signatures to derive
a recommended
result regarding the valve leaks; and digital storage means for storing the
digital data
representing the sound signatures and a conclusion or judgment derived from
the data and the
5
io recommended result. The conclusion includes the user's judgement on whether
there is a leak,
the economic need for repair, and the quantitative severity of the leak if
any. The invention also
includes a method comprising the steps of attaching a plurality of transducers
to the valve
system; operating the plurality of transducers to receive sounds from the
valve system and to
convert the sounds into electrical signals; fast Fourier or otherwise
transforming the electrical
signals to produce sound signatures and outputting digital data representing
the sound signatures;
comparing at least two of the sound signatures to derive a recommended result
regarding the
valve leaks; and storing the digital data representing the sound signatures
and the conclusion or
judgement (as defined above) in a digital storage medium.
In a broad aspect, then, the present invention relates to an apparatus for
performing a
2 o process of testing a valve system for a valve leak, the apparatus
comprising: transducer means
for receiving sounds from the valve system and for converting the sounds into
electrical signals;
transform means for receiving the electrical signals, for computing a
transform of the electrical
signals to produce at least two sound signatures, and for outputting digital
data representing the
at least two sound signatures; and computation means for (i) receiving said
digital data and
2 5 comparing said at least two sound signatures to obtain a comparison
result, and (ii) automatically
deriving a recommended result regarding whether said valve leak exists from
the comparison
result.
The comparison result may be a ratio of amplitudes of said at least two of the
sound
signatures at a selected frequency which is taken from the group consisting of
a manually
3 o selected frequency and an automatically selected frequency.
Moreover, the comparison result may be a ratio of foot mean squares of
weighted
amplitudes of said at least two of the sound signatures, the root mean squares
being calculated
over a predetermined frequency range.
Furthermore, comparison result may be a root mean square, over a predetermined
3.°~ frequency range, of weighted ratios of amplitudes of said at least
two of the sound signatures.
In the apparatus of the present invention, the amplitudes of the sound
signatures at a
dominant frequency may be summed to derive a sum; and the comparison result
for each valve
may be a ratio of an amplitude of that valve's sound signature at the dominant
frequency to the
sum.
CA 02173794 1999-06-09
3(a)
The apparatus of the present invention may further comprise digital storage
means for
storing the digital data representing the sound signatures and a conclusion
derived from the
recommended result and said at least two sound signatures.
The apparatus of the present invention may further comprise display means for
displaying
said at least two sound signatures and said recommended result. Such display
means may also
display a difference calculated from said at least two sound signatures.
In the apparatus of the present invention the computation means may comprise
an interface
means for receiving a user's input for at least one of planning, testing,
analysis and reporting of
1 o a test survey. Such interface means may comprise a touch screen.
The apparatus of the present invention may further comprise connection means
for
outputting the digital data representing the sound signatures and the
conclusion to an external
computer. Such connection means may comprise a port for a floppy drive.
The apparatus of the present invention may further comprise digital storage
means for
i5 storing an information database and a group of test structures for said
process of testing.
The computation means may comprise control and display means for guiding the
user in
understanding the process of testing. The computation means may also comprise
selection means
for controlling the interface means to enable the user to make choices
required for the process of
testing. Such selection means may enable the user to select a parameter and
may control the
2 o transducer means and the transform means so that the sound signatures are
produced in accordance
with the parameter selected by the user. Such parameter may be frequency
range. Such parameter
may be bandwidth. Such parameter may be transform type. Such parameter may be
averaging
type. The selection means may further control the apparatus to collect the
sound signatures in
accordance with the choices made by the user. The interface means may display
one or more of
2 5 the sound signatures simultaneously and the user may use the interface
means to indicate a portion
of one of the one or more of the sound signatures; the interface means may
generate a touch signal
and outputs the touch signal to the control means, which changes a scaling
factor by which the one
or more sound signatures are displayed on the interface means in accordance
with the touch signal.
The interface means may have a plurality of manners of actuation by the user,
and may comprise
3 0 help means for displaying, when the user performs a predetermined one of
the plurality of manners
of actuation, a context-sensitive descriptive message. The apparatus may also
comprise digital
storage means for storing a plurality of instructions for operation of the
computation means. In
this case, the transform means may comprise storage means for storing a
plurality of instructions
for operation of the transform means.
3 5 In another broad aspect, the present invention relates to a method for
testing a valve system
for valve leaks, the method comprising: (a) positioning at least one
transducer on the valve system
to receive at least two different sounds from a valve in the valve system and
to convert the sounds
into electrical signals; (b) transforming the electrical signals to produce
sound signatures and
outputting digital data representing the sound signatures; (c) comparing at
least two of the sound
signatures, based on said digital data, to obtain a comparison result; and (d)
deriving a
3(b) ~ ~ ~ 3 ~ 9 ~
recommended result regarding valve integrity from the comparison result and
displaying the
recommended result to a user.
In the method of the present invention, the comparison result may be a ratio
of
amplitudes of said at least two of the sound signatures at a selected
frequency which is taken
from the group consisting of a manually selected frequency and an
automatically selected
frequency. . -.~-- ~-,
In the method of the present invention the comparison result may be a ratio of
root mean
squares of weighted amplitudes of said at least two of the sound signatures,
the root mean
io squares being calculated over a predetermined frequency range.
In the method of the present invention the comparison result may be a root
mean square,
over a predetermined frequency range, of weighted ratios. of amplitudes of
said at least two of
the sound signatures.
In the method of the present invention, amplitudes of the sound signatures at
a dominant
~.5 frequency may be summed to derive a sum; and the comparison result for
each valve rnay be
a ratio of an amplitude of that valve's sound signature at the dominant
frequency to the sum.
The method of the present invention may further comprise storing the digital
data
representing the sound signatures and a conclusion derived from the sound
signatures and the
recommended result in the digital storage medium.
2 o The method of the present invention may further comprise (e) outputting
the digital data
representing the sound signatures and the conclusion to an external computer.
Step (e) may
comprise writing the digital data representing the sound signatures and the
conclusion onto a
machine readable medium.
The method of the present invention may further comprise a step of storing an
2 5 information database and a set of plans which are standard test structures
or modified test
structures derived from the standard test structures, said plans also
including automated analysis
structures. The method of the present invention may also include step (e)
comprising (i)
compressing the digital data representing the information database, plans,
sound signatures and
conclusion into a compressed file and (ii) writing the compressed file onto a
machine readable
3 0 medium. In the method of the present invention valves in the valve system
may be grouped into
items and given item numbers, each of the item numbers being identified by a
primary (group)
number and a sub number, a primary (base) item having a system-specific
function and all other
items having a function supporting the primary item. Each set of items grouped
under a primary
item may be assigned to one of said plans. Moreover, all items may be compiled
into an
3 5 ordered database having information categories including items, plans and
identification
information. Furthermore, the method of the present invention may comprise
repeatedly
searching the ordered database according to any of the information categories
for selecting an
order of group testing and separating results of such searching by test
completion. The method
may further comprise a step of displaying instructions which guide the user to
comprehend and
4 o conduct the method for testing. The method may also comprise a step of
enabling the user to
t r j'?~ c.
3(~) '~ ~~7 9~
make choices required for the method of testing. The step of enabling may
comprise enabling
the user to select a parameter, the sound signatures being produced in
accordance with the
parameter selected by the user. The parameter may be frequency range. The
parameter may
be bandwidth. The parameter may be transform type. The parameter may be
averaging type.
In the method of the present invention the sound signatures may be collected
in accordance with
the choices made by the user. When one or more of the sound signatures are
displayed
simultaneously and the user indicates a portion of one of the one or more of
the sound
signatures, a scaling factor by which the one or more sound signatures are
displayed may be
1o changed. The method may further comprise a step of displaying, when the
user makes one of
the choices in a predetermined manner, a context-sensitive descriptive
message. In the method
of the present invention, the step of displaying instructions may comprise:
(i) prompting the user
to secure the valve system in a proper configuration; (ii) in a case of
positive user response,
proceeding with the method of testing; and (iii) in a case of negative user
response, displaying
x5 a warning message; thereby promoting user safety and precluding invalid
signatures. Such
method may further comprise prompting the user to perform an operation
selected from the
group consisting of: (i) placing the transducers on a portion of the valve
system for testing; (ii)
reseating the transducers; (iii) saving a signature when the signature is
determined to be good;
and (iv) correcting a situation which causes an invalid signature.
Furthermore, the method of
2 o the present invention may also comprise selecting a highest signature of
two or three contiguous
signatures; marking the highest signature with a RMS difference repeatability
test result; and
determining whether the RMS difference repeatability test result conforms to a
predetermined
repeatability criterion; and if the RMS difference repeatability test result
does not conform to
the predetermined repeatability criterion, the step of displaying instructions
may comprise
2 5 instructing the user to reseat the at least one transducer. The method of
the present invention
may further comprise: (i) prompting the user to remove and reseat the
transducers and to repeat
signature collection; and (ii) calculating a RMS difference repeatability for
verification of proper
transducer placement. The method may further comprise directing the user into
test and analysis
completion of an item group in a proper order. In such a case, the method
further comprises
3 o permitting the user to advance to a position in the plan selected by the
user while maintaining
full test completion prompting. In the method of the present invention, step
(c) may comprise:
(i) displaying two or more signatures; (ii) receiving a user input
representing a selection of a
first signature and a second signature from the two or more signatures
displayed and a location;
and (iii) determining a difference between the first and second signatures at
the location selected
3 5 by the user; and (iv) displaying the difference obtained in step (c)(iii).
Step (c) may further
comprise determining the recommended result based on the difference and
displaying the
recommended result. The method may also comprise temporarily storing one or
more
recommended results until the user accepts them or enters conclusions
different from the
recommended results. Step (c)(i) may comprise automatically selecting pairs of
signatures for
4 o display, comparison and result recommendation.
n
3(d)
In the method of the present invention step (d) may comprise correcting the
sound
signatures for sound attenuation, said sound attenuation being a function of
frequency and
distance.
In the method of the present invention step (a) may comprise automatically
prompting
the user (i) to ensure that predetermined valves in the valve system are open
or closed, (ii) to
indicate that the predetermined valves have been opened or closed as prompted,
(iii) to attach
the transducers to predetermined locations on the valve system, and (iv) to
indicate that the
transducers have been attached to the predetermined locations.
i o The sounds are not received until the user has indicated in step (a) that
the predetermined
valves have been opened or closed as prompted and that the transducers have
been attached to
the predetermined locations.
In such a method, the user is automatically prompted to perform steps (a) and
(b) a
plurality of rimes for a plurality of configurations of opened and closed
valves in accordance
~.5 with a sequence stored in the automated interface device; step (b) may
comprise fast Fourier
transforming the electrical signals to produce the sound signatures and
displaying the sound
signatures to the user; and step (c) may comprise automatically calculating a
ratio of said at least
two of the signatures and automatically determining, in accordance with a
stored rule, the
comparison result in accordance with the ratio; and step (c) may further
comprise prompting the
2 o user to input the conclusion on the basis of the sound signatures
displayed in step (c) and the
recommended result. Step (c) may comprise receiving a user input indicating
which of the
sound signatures are to be compared and deriving the ratio from the sound
signatures selected
by the user.
In the method of the present invention, step (a) may include positioning the
transducer
2 5 at a plurality of positions on the valve system, or positioning the at
least one transducer in one
or a plurality of positions on the valve system and controlling the valve
system to provide a
plurality of differential pressures across the valve system.
In the apparatus of the present invention, the at least two sound signatures
may comprise
sound data for at least one frequency greater than or equal to 100 kHz.
3 o In the method of the present invention, the sound signatures may comprise
sound data
for at least one frequency greater than or equal to 100 kHz.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described more fully with respect to the drawings,
in which
Fig. 1 shows a block diagram of the apparatus according to the invention;
35 Fig. 2 shows an OK window in the user interface of the apparatus according
to the
invention;
Fig. 3 shows a YFS/NO window in the user interface of the apparatus according
to the
invention;
f.
3(e)
Fig. 4 shows a multiple/choice window in the user interface of the apparatus
according
to the invention;
Fig. 5 shows a numeric window in the user interface of the apparatus according
to the
invention;
Fig. 6 shows an alphanumeric window in the user interface of the apparatus
according
to the invention;
Fig. 7 shows a CONTROL PANEL in the user interface of the apparatus according
to
the invention;
LPL I ~~.~~~1~
4
Fig. 8 shows a LIS'C PANEL in the user interface of the apparatus according to
the
invention;
Fig. 9 shows a MAKE PANEL in the user interface of the apparatus according to
the
invention;
Fig. 10 slows a SIGNATURE PANEL in the user interface of the apparatus
according to the invention;
Fig. 11 shows a REVIEW PANEL in the user interface of the apparatus according
to the invention;
Fig. 12 shows an INFO PANEL in the user interface of the apparatus according
to
the invention;
Fig. 13 shows an ANALYZE PANEL in the user interface of the apparatus
according
to the invention;
Fig. 14 slows a CONCLUDE PANEL in the user interface of the apparatus
according to the invention;
Fig. 15 shows a tree structure for the use of the various panels in the user
interface
of the apparatus according to tl~e invention;
Fig. 16 shows the first part of a flow chart of tire initiali~ltion of the
apparatus and
the operation of the CONTROL PANEL;
Fig. 17 shows a flow chart of the "PICK ITEM" operation;
Fig. 18 shows the second part of the flow chart .of the initialization of the
apparatus
and the operation of the CONTROL PANEL;
Fig. 19 shows a flow chart of the "LOAD ALL" operation;
Pig. 20 shows a flow chart of the operation of the LIST PANEL;
Figs. 21 and 22 show a flow chart of the operation of the MAKE PANEL;
Figs 23, 24A, 2413, 25 and 26
show a flow chart of the operation of the SIGNATURE PANEL;
Figs. 27 and 28 slow a flow chart of the operation of the REVIEW PANEL;
Fig. 29 shows a flow chart of the operation of the INTO PANEL;
Pig. 30 shows a flow chart of the SAVE RESULTS operation within the INFO
PANCL;
Figs. 31-33 show a flow chart of the operation of the ANALYZE PANEL;
Fig. 34 shows a flow chart of tire operntion of the CONCLUDE PANEL; and
Figs. 35-37 show a flow chart of the operation of a digital signal processor
used in
the invention.
L~a~ i ~ ~ ~~
DETA1LCD DrSCRIp I'ION Or 'fIlr PRrrrRRPD CM)30D1MrNT
A presently working system according to the invention will now be described
with
respect to the block diagram of dig. 1. Apparatus 100 includes two
transducers, channel A
transducer 102 and channel B transducer 104, for taking sound readings from
the valves.
5 Signals from these two transducers go into, for example, fast Fourier
transformer (rFT)
module 106 or the like, where they are fast Fourier analyzed to yield acoustic
signatures.
CPU 108 controls storage of these sound signatures on hard drive or other
storage device
112 and the display thereof, as well as receipt of user input, on touch screen
or other user
interface device 110. The apparatus can exchange data with other devices
through port 114
for a floppy drive or the like. These components as provided in the presently
working
embodiment will tae described in further detail below.
The presently working system takes the form of a portable, battery-operated
laptop
personal computer (PC) with data collection software, a hardware FFT module,
spare
batteries, transducers and otlrcr accessories, all packed in a rugged case Ibr
in-plant use.
Separate, off-line battery chargers and a miniaturized printer can be
provided.
The working system measures 12.5 x 10 x 2.5 inches and weighs 10 pounds. A 12
volt, 2.3 amp hour, lead acid gel cell battery with quick exchange access
powers the
apparatus. A small rocker on/off switch on the lower right-hand side of the
system
constitutes the only external control on the system.
The display is a 6 x 8 inch backlit liquid crystal display (LCD) with video
graphics
array (VGA) resolution (640 x 480 dots). A transparent, pressure sensitive
panel covers
the full LCD. Moderate finger pressure registers a touch and release with its
horizontal and
vertical position. Thus, the touch of a certain firnction displayed on the LCD
replaces a
dedicated push-button on the system. Other constructed embodiments of the
invention have
included a conventional monitor and a mouse rather than a touch screen. Those
skilled in
the art who have reviewed this specification will understand which user
interface devices are
useful for which purposes.
'Iwo BNC connectors on tl~e upper right-band side of the system provide
Channel A
and Channel B transducer inputs. The Channel A input, toward the top, is used
for most
applications. Standard 100 kohm input impedance amplifiers are optimized for
use of the
transducers on almost any valve signature. Automatic gain controls, invisible
to the
operator, replace the external attenuation or gain switch critical to other
instruments.
The Channel A and Channel B transducer inputs go to the hardware FFT module
106.
This module includes an integrated circuit for effecting the fast Fourier
transform of the
C~~ i ~ ~~~~'~
6
signals received through the transducer inputs under control of code stored in
an EEPROM
or the like.
The operating program and test data are stored on an internal 80 Mbyte hard
drive.
Five connectors on the left hand side of the system allow the system to be
used as a
38GSX DOS-compatible computer. The serial port (COM1), external CRT, and
keyboard
connectors match most available peripherals. The floppy-disk connector is not
standard, but
is designed to be used with a 3'h" drive powered by the internal battery. A
backup drive
unit may be used in place of the floppy-disk drive; such backup drive units
are commercially
available and will not be described in detail here.
The transducers are e.g. accelerometers specially selected for their response
to
acoustic emission signals in the 10-200 kHz frequency range. Commercially
available
matched pairs of two types of transducers are preferably used. When used with
the
differential signature method, the transducers should be used in the factory-
matched pairs.
The preferred transducer is the most sensitive, especially at frequencies near
25 kHz,
and can be used without a standoff at temperatures ranging from -100°F
to +350°F. 1t
loses sensitivity if the cable length exceeds 3 meters. A second type of
usable transducer
is about 20 dD less sensitive and can be used to record signals that would
overrange the
apparatus if recorded with the preferred transducer. The second type of
transducer has a
temperature range which is -100°F to +350°I: It is most
sensitive at frequencies near or
above 50 kHz and can be used at cable lengths up to 19 meters without loss of
signal
strength.
The choice of transducers depends on the situation encountered, but once
chosen, the
same transducers, cable, and standoff must be used throughout a test.
Otherwise, the results
of various measurements cannot be compared to determine whether a valve leaks.
The transducer standoff is an 8-inch long by 3/e-inch diameter steel rod with
a ~h-inch
diameter ball end. The other end is threaded, allowing the transducer to be
attached by the
10-32 mounting stud. The ball end mates with the spherical indentation in the
disk. A small
amount of coupling compound should be applied at the transducer-rod interface
and the
ball-disk interface to assure a good acoustical contact.
The transducer standoff may be used as a hand-Meld probing tool to move
quickly
from one valve location to another or as an insulator to keep the heat of a
hot valve or pipe
from damaging the transducer.
If acoustic measurements on steam valves and, piping or other high-temperature
structures are desired, the transducer standoff must be used to keep the
transducer cool. The
transducer must not be allowed to exceed its temperature limits, or it will
become
permanently damaged or destroyed. A small amount of coupling compound is
required at
r
C~~1.7~194
all metal-to-metal interfaces. No excessive pressure is required if the
surfaces are free of
dirt and mated properly. The transducer end of the standoff should be held
while the
measurement is made.
The transducer cables are shielded, high-temperature coaxial cables with BNC
S connectors at one end and microdot connectors at the other end. Normally,
one 15-ft cable
is supplied with each transducer. Other lengths are available.
The software program resides on the root directory of the hard drive mentioned
above. Thus, it can be upgraded as needed with no need to change a ROM chip or
the like.
1'he external floppy drive referred to above can be used for this purpose.
l0 In oaer to develop a clear comprehension of the complex analyzer program,
the
building blocks will first be described, and then a step-by-step program
operation will be
described. In this description, the valves are grouped as a plant, a unit, an
item, a sub-item,
a plan or a series. The unit is the highest group and typically represents
several days' work.
An item is a particular assemblage of valves being tested and Is designated by
a whole
15 number. Decimal numbers indicate sub-items (particular valves or the like).
A plan is a test
structure defined in terms of a previously prepared assemblage of valves or a
modification
of a previously prepared assemblage of valves; a plan may represent a single
valve or
several. Fewer than a hundred plans can be used to cover almost all actual
situations. A
series is a set of signatures for all valves in an item. In a plan, any
assemblage of valves
20 can be defined as a system (e.g., preheat system, main steam system,
auxiliary steam
system, or lobe oil system). Parts of a system can be further defined as
subsystems.
1'he display and touch screen form a flexible function-key interface for
directing all
operator-instrument interaction. Every function key is an independently named
and located
touch zone on the display screen. In most cases, each function key is
identified by a word
25 or symbol enclosed in a finger-sized rectangle. The exceptions are
selection and display
changes, which are located directly on a signature. Any time an activated
function key is
touched, the rectangle will be highlighted until the function key is released.
If the finger
pressure is removed while within that rectangle, the appropriate command or
character is
recognized by the program. Then, the display changes to reflect that
selection. Typing the
30 first character of any function key on the external keyboard will also
produce the same
response. A mouse or other pointing device could also be used to actuate the
function keys,
the working environment permitting.
Function keys can produce tlu~ee types of responses on the display. Some
trigger an
action which results in a visible change to their own display. Others produce
a pop-up
35 window within the display requesting a single key, numeric or alphanumeric
response. The
LA~I~~1~4
g
third type actually changes the whole display to a new panel. This panel will
have a
different set of function keys on it.
Pop-up decision windows, as shown in Figs. 2-6, are used whenever the program
requires the operator to make an individual selection. There are five types of
selection
windows: the OK window of Fig. 2, the YESINO window of Fig. 3, the multiple-
choice
window of Fig. 4, the numeric window of Fig. 5, and the alphanumeric window of
Fig. 6.
The OK window announces a particular situation and waits for the user to
acknowledge it.
The YES/NO window asks a particular question and waits for the user to press
"YES" or
"NO". The multiple-choice window presents a key for each of the allowed
entries. After
one of the entries is pressed, the window is removed. The numeric window asks
the user
to type in a number selection. Of the various keys available in this window, "
< " removes
a digit, "RET" sends tire number to the program while removing the window, and
"ESC"
cancels any entry and removes the window. A default selection is shown in
parentheses.
The alphanumeric window requests a name or comment. Of the various keys
available in
this window, " < " removes a character, "RET" sends the character line to the
program
while removing the window, and "ESC" cancels any entry and removes the window.
If the
entry has already been started when this window appears, the previously
entered part is
displayed and can be extended or corrected.
To simplify organization and execution of a valve leakage survey, the program
breaks
down the task into manageable subtasks as much as possible. The instrument
presents on
the display only functions necessary to the task at hand. This task-related
group of functions
on the display is called a task panel. The various task panels will be
described with respect
to Figs. 7-14, which show the panels themselves, and Fig. 15, which shows a
tree structure
for the use of the panels.
There are three levels of panels. Movement between panels in the tree
structure of
Pig. IS is vertical. Operation always starts at CONTROL PANEL 700 of Fig. 7 at
the top
and proceeds down and then back up. A complete valve leakage survey entails
preparation,
valve testing and result reporting. This procession shows up as the left to
right ordering of
the panels: "LIST," "MAKE PLAN," "SIGNATURES," and "REVIEW," shown in Figs.
8-11 as 800-1100, respectively.
Program operation begins automatically when the power switch is turned on.
Initialization takes about two seconds. The unit, item and plan are loaded
from a status file
so that the user will have access to those settings last used. Operation then
proceeds from
the top, namely, the control panel.
The CONTROL PANEL has two main purposes. First, it defines the operating
environment of the test at hand. Second, it provides function keys 702-710 to
direct the user
C~~ ~ r'? 1~~
into one of the four second-level display panels, namely, "LIST," "MAKE PLAN,"
"SIGNATURES," and "REVIEW," or to the "QUIT" command to quit analyzer
operation,
respectively.
All operating data are filed under the 1UNIT directory. The use of this
directory
S Billows survey work to proceed on two or more independent groups of valves
without clearing
and reloading for each. Valve grouping cari be any level desired, such as
plant, unit, system
or subsystem as those skilled in the art will appreciate.
The unit key 712 is used to select the unit name, which is used as the
directory on
the hard drive to work with; in the DOS directory tree, this directory is
located directly
under \UNIT. This entry is rarely changed. One unit's work usually covers many
days.
Pressing this key lists the units already established. 'The previously active
unit is
highlighted. The user touches the unit name desired. Item loading will follow,
and the
control panel will return, displaying the results of the item load.
The correct unit should be verified at the top of the control panel every
time. An
incorrect selection can waste much work by using the wrong list and plans and
mixing up
signatures with those of a different unit.
The item key 714 pops up a numeric window to select the next primary item. The
default next item (in the list) is shown in parentheses. After a number is
selected, the series
is reset to zero. If the item is being selected for the very first time, the
primary item
subdirectory will be created. Then tl~e loading sequence is executed.
The plan key 716 lists the plans available within the particular unit. Most
selection
of plans should be done during building of the valve list and subsequently
designing any new
plans. The previously active plan is highlighted. The user touches the plan
desired. 1f a
change of plan is accepted, the program proceeds to reload the primary item
signatures. In
the illustrative example given in the figure, plan 20, which has five valves,
is shown in
piping diagram 701. 1n table 724 in the lower right, items .0 through .4 are
shown as closed
by X, open by O, or traps by T in each of steps 1 through 4. In this notation,
parentheses
indicate that a valve is under pressure, while slashes indicate that a valve
is not under
pressure, and d indicates that a differential signature (to be described
below) is needed for
that valve.
The series key 718 pops up the numeric window to accept entry of a series
number
between 0 and 15. The IBighest series which holds signatures is shown. The
user enters a
number between 0 and 15. If this number,is more than 1 higher than the highest
series used,
it will be reduced to prevent skipping a series. If a valid change of series
is accepted, the
program proceeds to reload primary item signatures. On the series key,
"series" is spelled
"xeries" so that the user can select either the series key or the signature
key by typing the
C ~ ~ ~i 7 .:~ ~ ~ 4
first letter. Of course, other conventions could be used, such as the
underlined letters well
known to users of graphical user interfaces. As shown, the current series is
series 0. Series
1 has a separate set of signatures and may involve a different test, e.g.,
after repairs rather
than before repairs.
S Only signatures saved under the selected series will show up as saved. The
user should
not mistake an incorrect series for a missing signature situation.
The frequency key 720 selects a frequency range, wherein 200 klz is the
standard
frequency range used for valve leakage signatures. A touch of this key
immediately changes
the frequency to the next selection of those available, 1001200/400/800 khz.
Under each
10 setting, any signature displayed and saved covers from 10% to 100% of the
frequency range.
The frequency is automatically set as signatures are loaded. The frequency
cannot be
changed after at least one signature is saved in a series. rrequency may be
changed by
advancing to the next series.
The average key 722 is used to select the average variable. There are two
purposes
of the average variable. The standard amplitude vs frequency signature display
uses average
as the length of time in seconds that the signature is averaged each time GO
is pressed.
Average = 0 means that only a single reading is used for the signature.
Touching this key
causes the value to alternate between 0, 1 and 2. The second purpose of this
variable is for
setting tloe length of time that is displayed in a time sweep signature
(amplitude vs time).
The list, make, signature, and review keys 702-708 switch, respectively, to
the list,
make, signature, and review panel analyzer operations, which will be explained
below. 'The
use of the signature key 706 presupposes the selected primary item, plan,
series, frequency
range, and average.
The quit key 710 terminates program operation. The analyzer returns to the DOS
' prompt and can then be turned off by the power switch.
Any time the item, plan or series is changed, the program automatically takes
the
following load sequence: it (1) searcljes for the primary item subdirectory on
the disk and
(2) loads any signatures already saved that fit the selected plan and series.
Saved signatures
are marked by a * in the plan.
Signature loading may lead to one of the following error messages:
"ERROR: Plan 1 used. Restore it?" If all signatures are saved under a
different
plan, that plan can be restored by a "yes" to this question.
"Warning: Multiple Plans Used." If some signatures were saved under a
different
plan, this note will pop up.
"Signatures Don't Match." If the plan has been modified and some signatures
saved
do not match the entry in the plan, this note will show.
11
"Latest Sigs 'Taken in Series I ." IF there are signatures saved of higher
series, the
highest series taken will be noted to help prevent mixing new signatures with
the old series.
The list panel 800 is a means to interrogate the valve list and display items
meeting
any selected set of criteria. The valve list is an ordered database having
information
csitegories (fields) including items, plans and identification information,
and is organized as
a hierarchical and relational data structure.' First the operator places an
entry in any number
of the fields of the search definition line 802. When the desired criteria
have been entered,
the operator presses the search key 804 to initiate the search and display the
results. Finally,
tire operator selects the item desired for collection and analysis by touching
the item. It will
be displayed at the top of the screen. The operator presses the TEST IT key
806 to return
to the control panel with the selected item.
All the fields except two use an alphanumeric text search. The search word can
be
any combination of letters, numbers, and certain puncrtiation characters, but
no spaces. 'Che
allowed length is the size of the field displayed. A match requires that the
complete search
, word be found anywhere within the corresponding field of a particular item.
Only the ilem and elevation fields use a numeric upper/lower limit search. The
operator must enter both an upper limit and a lower limit to search by these
fields. A match
requires that the corresponding field entry for a particular item fall between
the upper and
lower limits.
'lv enter a search criterion in a particular field, the operator touches that
field in the
search define area (lines 2-5). Touch the defined key 805 and the alphanumeric
or numeric
window will pop up. The operator then enters the word (or number) desired and
presses
RLTURN. RETURN with no entry removes any search criteria from that field. The
ESC
key 816 ignores any change of entry.
One example of a broad search is an entry in just the elevation field to
assist in
survey ordering by all valves located together.
1'he search key initiates a search of the valve list. Cach item in the list is
taken field
by field and is rejected if any field search word is not found within the
corresponding field
of that item. Only if all the fields match the search criteria is the item
displayed in the found
list.
A broad search might return many items in the found list. These will be
separated
into two sections with a dotted line between them. The items above the dotted
line are not
yet tested while those below the clotted line have already registered a
conclusion. Therefore,
as the list panel is repeatedly used in the course of a survey with constant
search criteria,
items will be selected from the top selection to go through collection and
analysis and will
then show up on the bottom section.
'' V 7
v~ ~l 7 ~~ ,: ~J ~+
12
To select an item, the user touches the item number. The user examines the
highlighted item line to verify the selected item as desired. If not, the user
simply touches
another item or redefines the search to produce a different found list.
After a particular item has been identified (highlighted), the TEST IT key
will take
that item number and return to the CONTROL PANEL just as if the operator had
pressed
the ITEM function and typed in that number. It will be ready to go to
SIGNATURES.
' The ESC key returns to the CONTROL PANEL with no change of item.
The up and down arrow keys move the cursor from the search definition area
through
the found list. The left and right arrows move the cursor horizontally only
within the search
definition area.
1'he MAKr PANCL 900 provides all the tools necessary to prepare a plan to test
any
primary item and its associated sub items. The analyzer does not place any
constraints on
the plan design other than a maximum of 15 valves and 15 steps (rows and
columns). The
number of sub items in the plan cannot be decreased to fewer than the number
showing
under List. The analyzer automatically places the optimum lineup entry, X
(closed) or 0
(open), to the left of each signature entry, (X) or /0/ or IXI or Xd. In this
notation,
parentheses indicate that a valve is under pressure, while stashes indicate
that a valve is not
under pressure, and the d indicates that a differential signature is taken.
"T" is a time
signature (infr~r). Some keys have a dual purpose in preparing the plan in
accordance with
whether valves or piping is selected first and highlighted. The differences in
purpose will
be explained in greater detail below.
The valves key 902 are pressed to enable the following firnctions of the MAKE
PANEL. They include all operations on the plan and on valves in the layout
drawing. One
valve in the drawing will be highliglUed.
7b place an entry into the plan table at the position of the plan cursor, the
user
presses one of the entry keys 904, namely, X, O, (X), lOI, IXI, Xd and T. If
the cursor
is on a sub item or a step, there is no effect. The various valves in the plan
are indicated
by decimal numerals, with .0 being the most important valve.
Pressing the MOVE key 906 allows the highlighted valve in the layout drawing
to be
moved. The arrow keys are next pressed to move the valve to the desired
location; when
done, the user presses the ESC key 908. The other keys do not function while
MOVE is
in process (MOVE key highlibhted).
' If the plan cursor is on a sub item, and there are fewer than IS sub items
in the plan,
a new sub item row will be opened in the plan when the INSERT key 910 is
pressed. If a
sub item row was previously deleted, it will automatically fill in this
inserted row. If the
r ~ ~,~~ ~ ~s ~y4
13
cursor is on a step number and here are fewer than 15 steps, a new step column
will be
opened up.
1f the plan cursor is on a sub item when the DELETE key 912 is pressed, that
whole
sub item row will be deleted, and the rows below it will move up. An INS can
be used to
restore an incorrectly deleted sub item row. If the cursor is on a step
number, that step
column will be deleted and any columns to the right of it will move over.
The four arrow keys 914 move the plan cursor around within the plan. If the
cursor
is on step number at the top of the plan, moving right beyond the last step
will add another
step up to 15 max. If the cursor is on a sub item number at the left of the
plan, moving
down below the last sub item will add another sub item to a maximum of 15. If
the cursor
is on a sub item number at the left of the plan, pressing the left arrow will
bring up the
alphanumeric window requesting entry of the plan valve description. It is
noted that the plan
will scroll horizontally and vertically to accommodate the limited display
size, and also that
the highliglned valve in the layout drawing will track the sub item that the
plan cursor is on
The piping key 916 enables the MOVE, INS and DEL functions to assume their
secondary purposes of operating on pipe sections in the layout drawing. One
pipe, if any,
in the drawing will be highlighted. These secondary purposes will now be
described.
Pressing the MOVE key allows the highlighted pipe of the layout drawing to be
moved. Next, the ARROW keys are pressed to move the pipe to the desired
location, and
finally, the user presses ESC when done. No other keys.function while MOVE is
in process
(MOVE key highlighted).
After pressing the INSEItf key to insert a pipe, an ARROW key must be pressed
to
determine the pipe orientation, horizontal or vertical. The highlighted pipe
will appear to
the right of the drawing. Next the ARROW keys are used to place it as in MOVE,
and
finally, the user presses ESC when done.
When the delete key is pressed, the I~igl~liglUed pipe, if any, in the drawing
will be
deleted.
Any ARROW key causes the highlighting to move among the pipe elements in order
to select the pipe section which the user desires to move or delete.
When the plan design is complete, the SAVE key 918 is pressed to save the plan
on
the disk drive. The display first lists the plans available within the present
unit. Then it
pops up the alphanumeric window to accept a name entry. Name entries can be
any unique
combination of up to four characters (frequently the names are just orderly
numbers to ease
record keeping). If the name selected is already in use, the YesINo window
asks for
verification to overwrite chat plan. After the plan is saved, the analyzer
leaves the MAKE
PANEL and returns to the CONTROL PANEL.
~~~~ i ~.5~y~
14
Actuating the CSC key causes the analyzer to leave the MAKE PANEL and return
to the CONTROL PANCL. If changes have been made, a YES/NO window requests
confirmation to restore the plan as last saved, and then return to CONTROL.
The purpose of the plan is to provide the organized stricture for testing and
analyzing
a particular group of valves. Most valve groups will fit into a standard pre-
tested and
optimized plan thereby reserving the MAKC PANEL for preparation for an odd
group or for
restructuring testing under restricted access conditions.
The remaining panels are used in valve testing and analysis. Their use will
now be
described.
One of the most important features of the analyzer is the semi-automated
signature
collection process. The SIGNAfURI: 1'ANI?L 1000, shown in l~ig. 10, leads the
operator
tlu-ough each pressure and background signature recommended in the plan
denoted by valve
diagram 1001 and W ble 1003. This leading follows the cycle of collecting all
signatures in
one step and then moving right in the plan table to the next step. A step
column in the plan
table represents all items (valves) residing in the indicated condition, as
well as the type of
signature to be collected at each item. Witlr reference to rigure 9, X =
closed valve; O =
open valve; (X) is closed valve pressure amplitude versus frequency signature;
/O/is open
valve background amplitude versus frequency signature; /X/ is closed valve
background
amplitude versus frequency signature; Xd is combined closed valve pressure
plus two
background amplitude versus frequency signatures; (T) is closed pressure
amplitude versus
time signature; and ITI is either closed or open background amplitude versus
time signature.
Moving to a different step in tire plan dictates changing the condition (and
thus pressure by
opening or closing one or more valves in a plan) of one or more valves. The
automated
collection process thereby gathers pressure and the background signatures on
all valves
required using a minimum of valve openings and closings. Normally it starts
with the plan
cursor highliglUing the first valve and first step. As shown in step 1, valve
.0 is closed, and
valves .2, .3 and .4 are open. 1f they are not already~in this state the
operator must open or
close them as needed to satisfy the condition indicated. Then a time signature
is taken by
hitting GO and then SAVC. The rest of the steps proceed similarly.
If beginner operation is selected, a valve alignment procedure is displayed on
startup
and each time the cursor moves between steps. A YES/NO window announces each
valve
the operator should set up and its position. If all the announcements For the
present step
are answered "YCS," the analyzer proceeds as normal. If any are answered "NO",
the
setup announcements for that step are stopped, but a warning will issue on
each GO.
The instrument advances the cursor to the first signature in the current step
and then
issues the message to place the transducer on the indicated valve and to hit
GO.
~~~'1 73 X94
Tlre user hits GO and the instrument responds with the message to hit GO again
until
repeatability (as described below) is satisfied. When it is satisfied, the
instrument prompts
flue user to hit SAV)r, then the user bits SAVC. The instnrment advances the
cursor to the
next signature in that step, and the above process is repeated for every
signature in the step.
5 The instnrment advances the curser to the next step and returns to the valve
alignment
procedure described above.
One signature can be collected for each (X), 101, IXI and (T) and ITI element
in the
plan. A differential element, Xd, requires three signatures. To collect these,
whenever the
plan cursor is on an Xd, an extra group of keys 1002 shows up just above the
plan table.
10 This group of keys takes the form shown for the single transducer
differential analysis by
default. In this case, the user will be prompted to position the transducer
and hit GO and
SAVC for each of the three locations, as described above. If the user wishes
to perform a
two-transducer differential analysis, he bits the MODC key, and then keys for
the two-
transducer differential analysis appear. In this case tire prompting asks the
user to place two
15 transducers at appropriate locations rather than just one, so that two
signatures can be taken
simultaneously.
The Go-Save routine is completed for each location by either manually touching
valve, or
one of the three keys 1002 or letting the analyzer automatically advance
through them. The
saved * in the plan table represents the valve signature of an Xd set while
the up and down
signatures saved are marked by the * on the corresponding keys.
Signatures displayed on the SIGNATURC PANEL are scaled by the ATTCN
(attenuation) selling. To shrink down the display, the user may touch anywhere
in the lower
half of the signature box. 7b enlarge the display details, the user touches
the display
anywhere in the upper half of the box. The ATTCN changes in steps of 5 dD from
-10 to
60 dD. A change of 5 dB eduals a magnification of 1.78, while 60 dB indicates
a
magnification of 1,000. The absolute signal amplitudes are determined by
adding the
A1'TCN value to the approximated dB nupber of floe peak as read off the left
side of the
signature. 1n the signature panel shown in Fig. 10, llre AI"1'CN setting is 35
dB.
The MODC key 1004 cycles through the available modes for a certain plan
element.
Mode changes the function of the BW key 1006, whose use will now be described.
Under modes A, B, and A-B, the MODC key switches the display smoothing
bandwidth between 1% and 3% of the frequency range. In time sweep mode, the
display
~shpws amplitude vs time. This amplitude is an average over a fixed frequency
band having
a width of 10% of the frequency range. When the BW key is pressed, the display
switches
G~~ ~ l ~~ ~~~-
16
to amplitude vs frequency. The transducer is placed on the trap (a type of
valve, as those
skilled in the art will appreciate) and the display is touched anywhere to
read a signature.
Next, the time sweep center frequency is chosen by touching the signature at
an appropriate
area of high signal. The dark bsrr under the signature indicates the frequency
band to be
averaged. Tlre Esc key 1008 is pressed.when the band selected is correct. The
display will
revert back to time sweep mode with the selected center frequency displayed
under the BW
key.
The CLR key 1010 removes any signature started by GO but not SAVED, allowing
the GO procedure to be restarted. It is used whenever the initial GO on a
valve produces
a non-repeatable signature due to a bad application of the transducer to the
valve.
The GO key 1012 starts G0, which is the central function of the whole
analyzer.
The most time is spent here actually testing valves. Any time the plan cursor
highlights a
signature type, namely, one of (X), lOI, IXI, Xd, and 'f, one of these
messages is displayed
under the CLR and GO keys and GO can be pressed.
"Place transducer, on item 1.0 and press GO." When GO is pressed, the analyzer
acquires the signature and displays it unless one of these messages appears:
"Not settled;
retake" or "CHECK: Resent transducer on Item 1.0 and press GO."
"Good repeatability; press Save." All signature elements in the plan except
for T
(time sweep) employ a repeatability test requesting more than one GO press.
The initial GO
at a particular plan element displays as a solid line. Subsequent GO readings
show as a
dotted line and are used only for repeatability checking. If it passes, a SAVE
is requested.
If it does not pass, the check message is repeated. If the initial reading was
not good (cannot
be repeated), CLR must be pressed to retake an initial.
GO on a time sweep starts a slow time trace of amplitude (see DW). The length
depends on the average set in the control panel. Tirne sweep signatures do not
request a
repeatability check because of their time dependent nature. Save is requested
when done.
If the present element already had a saved signature, indicated as "*" in the
plan, it
will be noted as "SAVED" on the signature, and will display as a solid line
until GO
acduires a new signature.
Each signature must be manually saved to keep it for further analysis by
pressing
SAVE after a GO has produced a repeatable signature. The solid line (initial
GO reading)
on the display will be stored on the disk drive under the proper file name.
The save function
may produce one of the following messages:
"Not stable, save anyway?" If the GO function could not produce a repeatable
signature, a SAVE can be carried out with a Y)=S to this question.
.~ ~ ~I ~ u~ ~' 4
17
"This series has data saved, Do you want to overwrite?" If a previous
signature was
saved at this Sub Item and Step, this YF.SINO window will request confirmation
to
overwrite. "Do you want to save to the next series?" If it is not desired to
overwrite (lose
the previous signature), then a YES answer to this window will automatically
advance to the
next series. The plan wilt reflect the saved status of all signatures in the
new series. The
series number is printed just above the plan.
1f there is a signature already saved at the present sub item and step, the
ERASE key
1014 will ask for a YES/NO confirmation and then erase the signature from the
disk drive.
This is used if the user does not plan to overwrite an improperly taken
signature.
SAVE also automatically advances the cursor through the plan to the next
uncompleted signahire. First it checks for the next signature to complete the
present step.
If no more are needed the cursor moves to the next step, follows the valve
alignment
prompting procedure and continues to check that step as above. 1f all
signatures are
completed, the message is display. "Plan Completed".
The INFO key 1016 switches the analyzer down to the INFO PANEL.
The ANALYZE key 1018 key switches the analyzer down to the ANALYZE
PANEL. This is commonly used after the plan is filled in with as many
signatures as are
reduired to obtain a recommended result and/or to draw a conclusion. The
ANALYZE
function does not have to be used immediately after taking the signatures on
the items in one
plan. A primary item can be reelected in the control panel and this function
accessed at any
time.
The ESC key 1008 moves the analyzer up to the CONTROL PANEL.
The LEFT/RIGIIT ARROW keys 1020 above the plan move the plan cursor between
steps of the plan. If the signatures elements in that step have not been
saved, a warning
message will appear. If beginner mode is enabled, the alignment check is
stepped through
each time.
The UP/DOWN keys 1022 below the plan move the plan cursor between the valves
(sub items) of the plan,
The valve layout drawing reflects both the position (valve) that the plan
cursor rests
on and the state of each valve at the cursored step in the plan. Closed valves
(i.e. X, (X),
IXI or Xd elements) are filled in the drawing. Open valves (i.e. O or l0l
elements) are not
filled in.
The REVIEW PAN)rI~ 1100 of Fig. 11 provides an overview of survey completion
atul outputs to feed the work to other databases.
The initial panel lists all primary item numbers having any signatures taken.
If any
results have been recorded, the date of the last will be displayed next to the
item number.
18
The review item key 1102 pops up the numeric window to enter an item number.
If RETURN is pressed, the display switches back to CONTROL PANEL and then to
signatures using the entered item. A more direct way to do this is simply
touch the item
number on the screen.
The LIST ALL KEY 1104 is pressed to see a full listing of completed
signatures,
results and comments. Those shown are only tl:e first series. First, on the
left is the item
number followed by columns of plan elements, each representing one completed
signature.
These elements are displayed as in the plan table except for uncompleted and
non-signature
elements not shown. Next, the extra series column is marked if signatures have
been taken
in additional series. That is followed by the results and then the comments
that have been
entered.
When the output key 1106 key is pressed, all results and comments are compiled
into
a file named RESULTS.CMP. 'this data can be directly imported into PARADOX for
reporting.
When the ZIP key llU8 is pressed, all work for the unit is zipped into one
file for
backup purposes. This includes VALVE 1.1ST, PLANS, SIGNATURES, RESUL'1~ and
INFORMATION FILIrS. 1'he file name is <Unit>.EXE. This file is a self
extracting
archive, as those familiar with archived files will know. After backing up
with the ZIP key,
the operator can QUIT from operation of the program and then use the DOS COPY
to copy
this file to a 3.5 inch floppy disk. 'The use of this size .floppy disk, of
course, is given as
an illustrntive example; those skilled in the art wlro have reviewed this
specification will
understand what other machine readable media (e.g., computer readable media)
can be used
and under what circumstances.
Restoration onto another computer is done by creating the proper directory for
the
UNIT, copying the zipped file to it, and typing the UNIT name, i.e.:
<Unit> Id to
where < Unit > is the name of the UNIT which the survey covers. For example,
if the unit
name is LAB2, the self-extracting archive will be named LAB2.EXE, and the
command to
restore the data will be LAB2 Id lo.
The ESC key 1110 returns the display to the CONTROL PANEL.
Fig. 12 shows the INFO PANCL 1200. As can be seen from this figure, the INFO
PANEL allows display and input of information about each valve.
Fig. 13 shows the ANALYZr I'AN)L 100. By comparing the signatures, the user
can determine the existence and severity of leaks by the differential
signature method
described above. It is also possible to automate (described below)
determination of the
~A~ i %S X94
19
dominant frequency and thus to automate signature comparison to obtain a
recommended
result, which the user can then accept or reject as a conclusion.
Pig. 14 shows the CONCLUDC PANRL l4tX). 1n this panel, column 1402 identifies
each item. Column 1404 identifies the result for each item, where L = leaking,
L2 =
probably leaking, T = tight, T2 = probably tight, NA = not applicable, and NT
= not
tested. It is emphasized that the CONCI.UDC PANIrL is a visual representation
of the
analysis performed by the device of tire invention. This analysis is deemed a
recommended
result. An operator may draw a conclusion from the displayed result and accept
the result
as is or override the result. Whatever decision is made by the operator, his
decision is
conclusive but, of course, derived after evaluating the recommended result.
The operator's
conclusion is entered through multiple-choice window 1410. Column 1406 gives
the
estimated size of each leak, small, medium, or large. Column 1408 allows a
free-form
comment for each valve including the user's conclusion.
Now that the user interface has been described, the procedures followed by the
program which controls the apparatus will be detailed with reference to the
flow charts set
forth in Pig. 16-34. Some of these procedures can be implemented in off the-
shelf business
software, such as PARADOX for data management, GXCEL or QUATTRO PRO for
numerical analysis, and WORD for report preparation.
The operation of the apparatus from switching on the power to selecting one of
the
lbur panels directly underneath tire CONTROL PANEL is shown in the flow chart
split
between rigs. 16 and 18. When the apparatus is powered on (step 1602), the
status file is
loaded (step 1604), and the item is picked in the PICK ITrM operation (step
1608; to be
described in fiuUher detail below with reference to rig. 17). The user can
then pick a unit
number (steps 1610-1616), in which case the item number defaults to 1 (step
1618), or can
pick an item number (steps 1620-1624), in which case the series number
defaults to 0 (step
1G2G), either way, the PICK I'fLM opersrtion begins again (step 1628). The
user can also
pick a plan (steps 1630-1636) or a series (steps 163.8-1644). Zither way, the
LOAD ALL
operation begins (step 1646; to be described in further detail below with
reference to rig.
19). Once the PICK ITCM or LOAD ALL operation finishes, the user is returned
to the
control panel. The user can also pick a frequency (steps 1802-1810) or an
average (steps
1812-1820). The user may also press QUIT (step 1822), in which case the
program is exited
(step 1824). Once any of these procedures except QUIT is done, the user may go
into LIST
(steps 1826 and 1828), MAKC (steps 1830 and 1832), SIGNATURC (steps 1834 and
1836),
or R>JVICW (steps 1838 and 1840).
The PICK ITCM operation will now be described with reference to Fig. 17. When
this operation is called (step 1702), it is checked whether the item number
designated is in
C~~ ~l .~r~:l
the list (step 1704). If not, the previous item is kept (step 1714), and
control is returned to
the operation that called the PICK ITEM operation (step 1716). If the item
number
designated is in the list, the item is set (step 1706), the valve information
is loaded (step
1708), the plan per list is set (step 1710), and the LOAD ALL operation is
commenced (step
5 1712). Once the LOAD ALL operation is finished, control is returned to the
operation that
called the PICK ITEM operation.
The LOAD ALL operation will now be described with reference to Fig. 19. Once
this operation is called (step 1902), for all subiu~::~s in the plan, ttre
valve conclusions and
external conditions are loaded (step 1904), and the lunitliteml directory is
searched (step
IO 1906). )each file name is checked to see whether it is for a signature
file, and the highest
signature series is held (steps 1908-1912). If the file is not the correct
series, and there are
more files, the search continues (steps 1914 and 1936), and if the series
selected is too high,
the series is reset (steps 1938 and 1940). If the file is the correct series,
the file is read to
see whether the signature should he loaded into the plan or whether there is a
signature error
IS (steps 1916-1934), and steps 1936, 1938, and (if needed) 1940 are rerun. If
the series
selected is not too high, the plan is checked (steps 144-1960), and control is
returned to the
operation that called the LOAD ALL operation (step 1962). There is also a
provision to
load a plan (step 1942) if no plan is selected or if a different plan was
used.
The operation of the LIST PANEL will be described with reference to Fig. 20.
20 When this panel is called (step 2002), it is displayed (step 2004), the
last search definition
is displayed (step 2006), and the working item is displayed (step 2008). Now,
the user may
define a search (steps 2010-2022), perform a search (steps 2024-2036), select
the working
item (step 2038), and then press either DO-IT to use the selected item (steps
2040 and 2042)
or ESC to keep the previous item (steps 2044 and 2046). Then the user is
returned to the
control panel (step 2048).
The operation of the MAKE PANEI. will be described with reference to Figs. 21
and
22. When this panel is callec! (step 2102), it is displayed (step 2104). The
user can now
move valves or pipes (steps 2106-2114), insert piping (steps 2120, 2122, 2116,
and 2118),
insert valves (steps 2120-2136), delete piping (steps 2138-2142), delete
valves (steps 2138,
2140, and 2144-2154), make entries (steps 2202-2206), use the arrow keys to
move the
cursor to a specific pipe section or valve (steps 2208-2216), or select piping
or valve mode
(steps 2218-2228). Then the user saves the plan (2230-2232) or escapes to
restore the
previous plan (steps 2234-2236); either way, the user is returned to the
CONTROL PANEL
(step 2238).
The operation of the SIGNATURE PANEL will be described with reference to Figs.
23, 24A, 24B, 25 and 26. When this panel is called (step 2302), it is
displayed (step 2304).
~~~ll~l~4
21
It is determined whether there is a signature entry at the cursor in the plan
(step 2306). If
so, it is determined whether the signature is already saved (and marked in the
plan with an
asterisk) (step 2308). In accordance with this determination, the user is
guided through the
steps of taking a signature (steps 2310-2314), or the saved signature is
displayed (step 2316).
When the DW button is hit (step 2318), the type of signature entry is
determined (step 2320).
If the signature is a frequency signature, the user is given the option of
switching display
smoothing between 1 % and 3 % (step 2322). : ~ tae signature is a time
signature, various
options are provided for displaying the frequency signature (steps 2324-2338).
When the "GO" button is pressed (step 2402), the user is guided through the
steps
of collecting a fi-equency signature (steps 2408-2452) or a time signature
(steps 2454-2466).
An important function of the SIGNATURE PANCL is the determination of
repeatability of signature taking. The measurement of valve acoustic noise by
a transducer
is dependent upon good coupling of the noise into the transducer. Although it
is impossible
to verify maximum coupling with 100% certainty, experience has shown that the
maximum
attainable coupling fUC a particular valve is repeatable to better than 1 dB.
This attainable
signal is then a function of the transducer contact force, angle and coupling
compound used.
Sensitivity to each of these conditions shows greater than 60 db variation in
level. Thus, the
only condition which produces a stable level, assuming human control, is the
maximum
attainable coupling.
The operation of the SIGNATURE PANEL automatically performs the following
repeatability measurement on every signature collection, while providing the
user with the
needed instruction messages to carry out the user operations indicated:
1. The user seats the transducer on the valve and hits GO (step 2402). The
first
signature produced at a valve is displayed as a solid line (S1) (step 2448).
2. The user lifts the transducer, reseals it on the valve and hits GO again.
This second
signature is displayed as a dotted line (S2) (step 2430).
3. The system computes the following:
Repeatability =~E(S1(f)-S2(f))2 /~E(S1(f))2
where S1(f) is the magnitude function of frequency and lJ is a sum over the
10% to 100%
frequency range (step 2436).
4. The user goes back to step 2 to retake another S2 and compare it to S1 if
the
repeatability is not less than 10% (1 c!B) (step 2446).
If the repeatability is less than 10% (1dB), the signature is good. If not,
the user
goes back to step 2 or 3 according to the message (depending upon the 2nd
level
~~~1~~~~y~
22
repeatability). This repeatability criterion is adjustable. Prior processes
required human
judgment, which varied from operator to operator.
The second level repeatability check is a test (not conclusive) of the
variation of the
signature with time while the transducer is held in one position. Each time GO
is hit, either
two or three signatures are taken quickly. If prey do not repeat by the same
criteria as
above, the highest is kept but marked as unstable.
The repeatability will come out OK only if that first signature was stable. If
it does
not, either the cause is poor transducer couplinL at SI, or the system is
unstable (background
noise or pressure). An appropriate message i~ displayed leading the operator
to a good
signature or a conclusion of time varying instability. In that case, a
differential or time
signature might be able to support a conclusion.
Anytime a signature is displayed, the user can change the attenuation by
pressing the
upper or lower half of tire signature (steps 2468-2480). After a signature is
collected with
the GO button, the user can choose to save the signature (steps 2502-2524) or
to erase il
IS (steps 2526-2542). If the user needs to skip some signatures or complete
them in a different
' order, he can use the arrow keys to move the cursor to a different item
and/or step in the
plan (steps 2610-2626). 1n addition, the user c.:, choose the INFO PANEL
(steps 2602 and
2604) or the analyze panels (steps 2606 and 2608), or to escape and return to
the control
panel (steps 2628-2634).
The operation of the REVIEW PANEL will be described with reference to Figs. 27
and 28. When this panel is selected (seep 2702), it is displayed (step 2704).
It is possible
to review an item by number (steps 2706-2716) or to list all items (steps 2718-
2748). It is
also possible to output information (steps 2802-2814), to zip the unit into
the self extracting
archive described above (steps 2816 and 2818), or to escape to the control
panel (steps 2820
and 2822).
1'he operation of the INFO PANI~I. will be described willr reference to Fig.
29.
When this panel is selected (step 2902), it is displayed, including the valve
information,
results table, and external flags (step 2904). At this time, the CONCLUDE
PANEL may
be selected (steps 2906 and 2908), or the user may move to the next sub-item,
if there is one
(steps 2910-2916). 'The arrow keys may be used to move the cursor to different
series in
the result table (steps 2918 and 2920). When the externals field is touched,
(step 2922), the
externals pointer is moved to the field touched (step 2924), and the externals
flag is toggled
on/off (step 2926). When the escape key is touched (step 2928), the results
are saved (step
2930; saving results wi~l be explained below with reference to Fig. 30), and
operation is
returned to the control panel (step 2932).
%l ~~
23
The operation of saving results will be explained with reference to Pig. 30.
When
this operation is called (step 3002), it is determined whether there have been
any result
changes (step 3004), and if so, the user is asked whether they are to be saved
(step 3008).
If there are no result changes, or if the user elects not to save them,
control is returned to
the previous operation (step 3006). If the user elects to save the result
changes, each sub-
item is saved in turn (steps 3010-3016), arid control is returned to the
previous operation
(step 3018).
The operation of the ANALYZE PANEL will be described with reference to Figs.
31-33. When this panel is called (step 3102), it is determined whether the
cursor is on a
differential signature (step 3104). If so, the procedure of Pig. 33 will be
followed, as
explained below. 1f not, the signatures to display are marked based upon the
cursor position
in the plan (step 3106), and the ANALYZE PANEL is displayed (step 3108). The
user can
select items with the up arrow (steps 3110-3118) or with the down arrow (steps
3120-3130)
or may go to the Results panel (steps 3132 and 3134).
When the SELECT button is pressed (step 3202), the user can select a sub-item
with
the numeric keypad (steps 3204-3212). With the DIC' key, the user may display
the
difference between any two signature windows jn a third window (steps 3214-
3218). The
1NF0 key calls the INTO PANEL (steps 3220 a:;d 3222). The left and right
arrows move
signatures left and riglU to view other steps (steps 3224 and 3226). The ESC
key saves
results and returns to the control panel (steps 3228-3232).
The operation of the ANALYZE PANEL in the case of a differential signature
will
lie explained with reference to Pig. 33. In this case, the upstream, valve,
and downstream
signatures are displayed on the top row, while the valve-upstream and valve-
downstream
differentials are displayed on the mid row (step 3302). Then, the user can go
to the
CONCLUDE PANEL (steps 3304 and 3306) or select a sub-item and a step with the
numeric
keypad (steps 3308-3318), in which case the selected signatures are displayed
on the bottom
row (step 3320). The user can also escape to the CONTROL PANEL (steps 3322-
3326).
ST~NATURE COMPARISON Tl?CI1NIOUP.S
The software performs valve leakage analysis by signature comparison. Valve
leakage analysis is usually a complex issue. Three factors must be resolved.
First, leakage
noise has a significant but predictable coupling between valves in a system.
Second, multiple
leak sources must be identified. Third, external background noise sources
(e.g., pumps,
condensers) can mask leak noise. Therefore, there are times when changing
valve
openings/closings are not sufficient or possible to positively identify leak
sources and sizes.
In these cases, the following differential methods are used.
t;~~ ~l i S ~~4
24
The differential methods automate the general method of signahrre comparison
where
two signatures are subtracted in one display to give better visual resolution
of amplitude
comparison and eliminate the human errors of the previous manual processes.
The operator
analysis and also the automatic analysis then take into account the noise
coupling function
as follows. Noise is attenuated as it travels down a pipe from one valve to
the next. This
coupling is a function of frequency with attenuation at a frequency given in
d13 per length
as measured in units of pipe diameters. The attenuation increases
approximately in ftmction
of the square root of frequency. Por example, the attenuation between two
valves ten pipe
diameters apart mibht lie l0 d13 at 120 kIIz but .-;nly 1 dI3 difference at 20
kIIz. Thus, an
analysis should place more weiglU on the observed difference at the higher
frequencies.
The following three differential methods start with the most general and move
to the
more complicated and specific.
(1) Signature Comparison Method
Any plan has the option of displaying the difference between two signatures in
the
Analyze Panel. I-Ieretofore these signatures were recorded on different sheets
of paper for
visual analysis by the operator, and the difference was neither calculated nor
displayed.
Certain simple plans have an automatic additio.. :.~ Difference displays; in
the case of only
a few valves, the plans store information indicating which signatures are to
be used. In
addition, the D1r k,:y can manually display the difference between any two
signatures
already showing on the Analyze Panel: Difference = Sigl - Sig2. The user
touches the first
signature, then the second signature, then the Dif Key, and finally, the
location to place the
difference display. This method produces an exact difference between
signatures at different
valves and/or different steps.
Certain standard plans have an automatic setup to display several difference
signatures. ror example, the simplest is Plan 1. It displays pressure-
background both across
the valves and across the steps. An operator can quickly judge the results
upon entering the
Analyze Panel.
(2) One Transducer Differential Signature
Differential signatures are used where it is not possible to remove pressure
from a
valve to obtain a background comparison signature. This method employs a
single
transducer and takes tluee separate signatures to compare a valve with
background noise on
either side of it. It assumes that the signatures are stationary over the time
of collection.
The three signatures are sequentially taken on the valve, upstream of it and
downstream of
it. Up and Down can be on another valve or just the pipe. Although a greater
separation
of up, valve and down locations is desired, ,,.:..:'::1 comparisons can be
made just off the
valve onto the pipe.
~~ awl i'~ ~9~
This set of three signatures is marked by one Xd in a plan which then brings
up three
extra keys above the plan. After collecting the signatures, the user hits
Analysis with the
plan cursor on the Xd. A dedicated Analysis Panel will come up showing the
three
signatures on the top line and two difference displays, Valve-Up and Valve-
Down, on the
5 middle line. The system will then automatically produce a recommended result
indicating
whether or not there is a leak by performing one of the analysis procedures
described below.
(3) 'Itvo Transducer Differential Method
In certain cases where the valve condition cannot be changed and background
conditions are unstable, signatures must be taken simultaneously at two
locations selected
10 from the valve and at up and down locations relative to the valve. This
method prevents
false readings due to a ;,hinge in conditions between signatures. Tlu~ee
transducers would
be difficult to manage simultaneously, but only two at a time are required to
produce valid
signatures.
When the cursor is on an Xd in the Signature Panel, the user hits Mode to
change
15 to two channel collection. Two keys wiil appear instead of three above the
Plan with the V
U key highlighted. The user places the channel A transducer at the valve
location and the
channel B transducer at the Up location and hits Go. After saving this, the
highlighted key
will automatically switch to V D. The user repc;ats the Go with the channel B
transducer
placed at the down location and saves this. The ,;;peatabilily is complicated
in this method
20 due to the necessity to reseal both transducers properly.
The V-V key IS 111 Opt1011 key used to acquire a differential signature with
both
transducers located on the valve. If taken, the V-V signature is used to apply
a transducer
sensitivity correction function to the channel D part of llre differentill
signatures in the
display and automatic anllysis as follows:
25 C~Y(f) = S2~Y(f)/S l ~~(f) both transducers on Valve
C2'(f) = S2(f) * CY~(f) applied to channel B at Up and Down
Analyze Panel display 1nd automatic analysis .proceeds almost the same as in
the one
transducer method above, except both valve signatures (fibm V U and V D)
appear on the
top line, the up and down signatures appear on the middle line, and the
difference signatures
on the bottom line.
AUTOMATIC PROCEDURES FOR ANALYSIS QF SIGNATURES
Automatic analysis, My which the invention automates a process which was
previously
performed manually, will now be described with reference to examples which are
meant to
be illustrative ratter than limiting. For instance, the equations used are
examples and
specific numeral citations can be used to fit the situation at land.
~~~175~94
2ti
The most important factor' in proper application of automatic analysis is the
selection
of signatures upon which to base recommendations. One assumption is that the
plan has
been properly designed to represent all the valves affecting pressures and
leak noise
contribution. Another is that the proper valve alignment has been established
to produce
pressure and no pressure conditions called for in the signature type. The next
most
important factor is the amplitude criteria used to quantify leakage. Another
optional factor
is tire frequency weighting function applied to each signature as it is fed
into the amplitude
criteria calculations. Usually, the weig!rting function emphasizes the higher
frequencies, i.e.,
W(f) _ ~2 * f/ Range (unity mid range). 'this is due both to lower transducer
sensitivity
with increasing frequency and to the acoustic ;,ttenuation with frequency de-
emphasizing
background noise. An operator selected semi-automatic method described below
adds a band
select limiting to the weighting, i.e., W(f) = 0 below f~ -.OS*Range and above
fb +
OS*Range.
1n operator-selected two-signature analysis, each time the operator uses the
Dif key
in the Analyze Panel, a ratio R is calculated of the two signatures chosen.
1'he total band
Differential Signature Entry Analysis (r, ASAmax and result where ASA =
acoustic
signature amplitude, which is the sum of attenuation and relative amplitude)
is displayed in
the upper right corner of that difference display. 'I'Iris display is
automated; previous
processes required that the operator record attenuation and calculate the ASA.
The Band key
and then any peak on the difference display are hit to replace the analysis
with a band limited
analysis at tire dominant frequency chosen.
One main advantage of organizing valves into standard plans is to apply proven
standardized analysis methods to them. As the methods are proved, they can be
added to
specific plans by the program. They could include any number of different
comparisons as
described above. The method of ratio calculation is individually selectable
for each
comparison, and the frequency weighting function can be applied or ignored for
each. Then
the result dependency for each item is selected as tlje maximum/minimum of one
or more
of the comparisons and the limit criteria are m~~iCed if necessary.
This analysis technique preprogrammeu into the plan can still be temporarily
overridden in the Analysis Panel by the use of the Band key calculating a
dominant
frequency ratio.
Differential signahrre entry analysis is a specific preset example of the
above and uses
p6int-by-point ratio criteria (explained below) to calculate R for both Valve-
Up and Valve-
Down. 1'he lower of these and the Valve ASAmax are taken to apply to the
Absolute Result
Specification.
~A~1731~4
27
When a group of parallel valves under matched conditions cannot be operated, a
direct comparison analysis can be done to calculate relative leak rates among
the group. The
most dominant frequency is selected over the group. The ratio of each
signature amplitude
to the sum of all the signature amplitudes at the dominant frequency is the
proportionate leak
rate.
Three kinds of ratio criteria will now be explained. The signatures to be used
can
be selected manually or automatically as needed. Por example, if adjacent
signatures in a
row or column are valve and background signatures, they can be automatically
selected. In
single-frequency ratio criteria, at an operation-selected frequency f, the
ratio is calculated
as:
R = S1(f) / S2(f)
The dominant frequency is selected automatically at the highest peak of a
frequency
weighted signature. If the highest peak is found at the lowest frequency, the
next highest
is selected. Manual selection with the Band key can be anywhere; however, it
is again
automatically maximized within 8% of the frequency touched. At the selected
frequency,
the ratio is
R = S 1 (f) / S2(f)
In RMS ratio criteria, the ratio of RMS is calculated thus:
2O SRMSt ='~E(S1(f) * W(fj)Z I E W(f)
SRMSZ = ~Fr(S2(f) * W(~)Z / E W(~
R = SRMSt / SRMS2
In point-by-point ratio criteria, the RMS of the ratio function is calculated
thus:
C(f) _ (S1(f) - S2(fj) l (S1(f) + S2(f))
R=E(C(n*A(~)/EA(~
V ='J (E(C(~2 * A(1)) - (E (C(n * A(n))2/ l: A(~ ) / E A(~~ where
R is the weighted signature difference ratio (-1 < R, < 1);
V is the variance of the weighted signature difference;
S1(f) is the magnitude function of frequency and ~ is a sum over the 10%
to 100% frequency range for each f where S1(f) or S2(fj > 12 dB ASA; and
A (fj is a second weighting function to discount lower amplitude frequencies
and to take into
account the sound attenuation (which is a function of frequency and distance)
of a linear
system:
~A~ ~i 7:'. ~~4
28
A (fj = 1 (S1(fj+S2(f)) + (Slmax+S2max) > .1,
= 10 * (S 1 (f) +S2(f)) / (S 1 ma:; -I-S2max) otherwise.
This approach bypasses the W(f) function.
The ratio, once calculated, may be used to determine the existence and
severity of
a leak thus:
Large leak: R ~ 25 dB
Medium leak: 25 dB > R ~ 10 dB
Small leak: 10 dB > R >_ 0 dB
Tight: R < 0 dB
Absolute result specification uses R and V thus:
Tight: R < O, V < .2
Leak: R > .3, V < .2
Otherwise, operator judgment is required. If a leak is found, the size of the
leak is given
automatically from the maximum ASA of the smoothed valve signature:
Large: ASAmax ~ 55 dB
Medium: 55 db > ASAmax Z. 35 dB
c
Small: ASAmax < 35 dB
ror steam traps, a time survey analysis is required. The system takes a time
sweep
signature of average amplitude over a 10% ba~:;:;u:lth centered at a selected
frequency. The
frequency can be selected when the operator hits BW. A standard frequency
spectrum
I appears by itself. The user touches a peak on the signature, and that
frequency is selected.
When Go is hit, a time signature records average amplitude for either 30, 60,
or 120 seconds
(set by Avg on Control Panel).
Automatic analysis first identifies open and closed states on the pressure
time
signature. Maximum amplitude (Amax) is calculated as the average of the
highest 5% of
points and minimum amplitude (Amin) is the average of the lowest 10% of
points. If the
ratio Amax/Amin is less than 5 dB, it is called stuck shut. If a background
(no pressure
time or frequency signature) is completed on the trap, it can be further
classified. The
average amplitude of the pressure (Pav) and ba:.i;ground (Bav) signatures and
the ratio of
PavIBav are calculated. If the ratio is greater than 20 dB, it is called stuck
open. If the
ratio is less than 5 dB, it is called stuck shut.
If the trap is not stuck shut, any point above (Amax+Amin)/2 is called open
while
points below are strut. The result is classified as:
.. Cl~~ 173 i ~4
29
railed Amin/Bav > 3 dB
or length of all Open periods < 5 sec
or time between start of Open periods > 15
Satisfactory otherwise
Any time the . Analyze Panel calculates a recommended result, it is displayed
automatically in the CONCLLJDI: I'AN)rL~but marked as recommended (flashing).
When
the user touches a recommended result in the CONCLUD1? PANCL, it becomes an
accepted
result which could be changed manually by touching it again. If not accepted
before
returning to the CONTROL PAN13L, all recommended results are lost.
lU 'fhe operation of the CONCLUD>J PANrI~ will be explained with reference to
Pig.
34. Cssentially, machine-recommend insults are displayed which can be accepted
or rejected
by the user in formulating his conclusion. When this panel is called (step
3402), the insults
table is displayed (step 3404), with the item, result, size, and comment for
each item under
the primary item. The user may enter a conclusion, namely, whether a leak is
judged to
exist (steps 3406-3410), the estimated size of the teak (steps 3412-3418), or
a continent
(steps 3420-3424). The user may also fill any items below the cursor not
having a result
with a copy of the cursor item line (steps 3426 and 3428) or escape to the
control panel
(steps 3430 and 3432).
A useful feature of this invention is the use of multiple prompting levels.
Signature
collection for leakage requires a complex plan procedure.with as much
information collected
as possible. Only after much experience can an operator recognize unnecessary
steps in
specific circumstances. Schedule pressures usually dictate maximum testing
speed.
1'hcrefore, the system has two types of process t::ompting two user selectable
levels. Some
are displayed at either level and others only at full prompt level. They help
to expedite and
minimize training required.
The system remains at the process prompting level set until reset by the
following
method. The user quits from the Control Panel to go to DOS and restarts the
system adding
the appropriate argument as follows:
AVLA/b for Full prompt Level
AVLA/e for Cxperienced Level
The first type of prompting is the status mes~wb~s displayed on the left above
the piping
diagram. Most of these show at bath levels. Instmctions for signature
collection follow this
order:
~;~,~ ~ l~~y~+
Place Transducer on Item 5.1 hit Go
CI-I)rCK: Reseat Transducer on Valve 5.1 and hit GO
Good Repeatabili:.; '..it Save
Plan Completed
5 Other messages include:
Not Settled Retake
' Not A Signature Step
No Data Acquired
The full prompt level adds some other messages
10 Step 1 alignment not completed
The second type of prompting uses the YCS/NO window to ask a question and
receive a response. Although it is used widely through the panels to help
prevent making
a mistake and losing data, this description mainly details its use in
signature collection at full
prompt level. Valves are grouped under a primary item with a plan testing
stmcture. A
15 plan will provide a signature entry for every combination of valve
pressures (open/closed)
necessary to resolve any possible source of leakage.
An inexperienced operator needs to follow a fixed procedure of valve
opening/closing
and signature collection. Actually, the most important reason is to observe
plant safety and
prevent open flow paths. Tire system aids this by leading the operator through
each detail
20 of the process of valve alignment, selling the user which valves to open
and close and which
signatures to take in each step, in addition to the above-described signature
collection
messages. Upon starting and after each step in the plan is completed, a
sequence of
questions show in the YI:S/NO window as in the following example:
Close Item 5.1 - READY?
25 Open Item 5.0 - READY?
Open Item 5.2 - RCADY?
Note that proper plan design (not overriding the automatic entry placement in
the MAKE
panel) will place valve closings in a non-signature step preceding valve
openings, thus
automating the valve alignment process and signature entries. The system will
automatically
30 move the plan cursor, ask the valve openingslclosings and request necessary
signature
collection. Advancement through the plan is first up/down and then left to
right. If the
operator bypasses a signature, the system tries to return to it before
advancing to the next
Step. If the operator tries to move to a different Step with the arrow keys, a
YESINO
question requests confirmation:
Step N01' completed, are you sure?
LA~~~ l~~'~~
31
The system remembers when the user performs actions out of the predetermined
order
and prompts the user to perform all necessary actions. Thus, even when the
user varies the
order, all necessary actions are performed; otherwise, some might be skipped.
A related feature, and one of particular interest to inexperienced users, is
the help
function. If the user is not sure how to use any particular key, he can hold
down the key
for at least one second to receive a descriptive, context-sensitive help
message. If he presses
and releases the key within one second, the key performs its normal function.
Of course,
other actuations could be used, such as the use of a right mouse button for
the help message
and a left mouse button for normal operation. Alternatively, a help key,
analogous to the
F1 key used in many standard applications, can be provided. Battery life
indication and a
brightness control for the display can be built into the help feature.
Finally, the operation of digital signal processing performed in FFT module
106 will
be explained with reference to Figs. 35-37.
When the FFT module is initialized, the following defaults are set (step
3502):
analysis = FFT, gain = mid-scale, range = 200 kHz, and frequency band = 92 kI-
Iz. Then
a user command is awaited (step 3504).
At this stage, the user can reset the analysis mode (steps 3506-3510) or the
sample
rate (steps 3512-3516) or issue a wakeup command (step 3518). In the case of
the last
option, "U" is sent (prep 3520), and the FFT module samples and processes
analog data (step
3522, to be explained below with reference to Fig. 36) and awaits any command
(step 3524).
Now the user can set the band (steps 3526-3530), sum over the band (steps 3532-
3536), have
processed data sent from the A channel (steps 3542 and 3544) or the B channel
(steps 3538
and 3540), set the filter and channel (steps 3546-3550), or put the module
into idle mode.
The step of sampling and processing analog data will be explained with
reference to
Fig. 36. When this step is called (step 3602), in accordance with the number
of channels
set (step 3604), the module samples either 16,384 points over one channel
(step 3608) or
8,192 points over two channels (step 3606). Then, in accordance with the
process type
selected (step 3610), the module performs a FFT (steps 3612-3620), an
autocorrelation (step
3624), or an envelope calculation (steps 3626-3632). If the amplitude peak is
over or under
range, the gain may be decreased or increased automatically as required (steps
3634-3642),
and the original process is returned to (step 3644). Previous processes
required manual
judgment and recording of the proper gain.
The step of sending the processed data, as in steps 3540 and 3544 of the
operation
of the I=FT module, will be explained with reference to Fig. 37. When this
operation is
called (step 3702), the gain is sent (step 3704), and it is determined whether
the signal
amplitude is within range (step 3706). If so, every two magnitude points are
averaged, and
CAS y !~5!~~4
32
data from 10% to 100% of the range are sent (step 3712). If not, it is
determined whether
the signal amplitude is under range at the maximum gain (step 3708) or over
range at the
minimum gain (step 3710). If either of these conditions is met, step 3712 is
executed. If
not, step 3712 is not executed. The original process is returned to (step
3714).
The above description is meant to be illustrative rather than limiting. Those
skilled
in the art who have reviewed this specification will understand that other
embodiments may
tie made that fall within the scope of the invention. ror example, the
apparatus may be
equipped with a bar-code reader for use in plants that have bar-coded valves.
Also, a color
screen can be used to superimpose signatures. Instead of fast Fourier
transforms, other
transforms may be used, such as lime domain transforms, correlation,
convolution, and
band-limited time correlation. Instead of software, firmware or the like could
be used to
guide the user and to perform analysis. Those skilled in the art who have
reviewed this
specification will readily understand how to make the modifications
appropriate for their
purposes without departing from this invention.
