FR2734054A1 - Leak detector for fluid transport valve system - Google Patents

Abstract

The detector has two acoustic sensors (102,104) for two channels (A,B). The electrical signals produced are sent to a FFT module (106) where they are converted by a fast Fourier transform to acoustic signatures which are stored by a processor (108) onto a hard disc (112). The processor automatically compares signatures from the valve itself and from pipes upstream and downstream and displays them on a tactile screen (110) enabling the nature of the leak to be determined. The screen offers a user interface giving step-by-step instructions for conducting a leak test, and a port (114) enables communication with other equipment.

Description

FIELD OF THE INVENTION
The present invention relates to the acoustic emission detection of leaks in valves that carry fluids and, more particularly, to an apparatus and method for using hardware and software for the purpose of rendering acoustic emission detection automatic. leaks in valves.

DESCRIPTION OF THE PRIOR ART
Systems for transporting gas or liquid typically contain many valves that may leak. One method for detecting leaks in the valves of such systems is the differential signature method which is described in the following documents which are incorporated by reference in this specification:
Dimmick, et al., "Ultrasonic leak detection cuts valve maintenance costs", Power Engineering, August 1986;
AVLATM Acoustic Valve Leak Analyzer Operators Manual 1989 (Acoustic Analysis User Manual for Valves), Leak Detection Services, Inc .; and
AVLA Acoustic Leak Analyzer Test Engineer's Valve
Guide, 0 1989 (Test Engineer's Guide for Acoustic Valve Analysis), Leak Detection Services, Inc.

 The differential signature method consists in measuring acoustic signatures defined as the amplitude of ultrasonic signals as a function of frequency or time at a given frequency, these signals emanating from a control point. Typically, three acoustic signatures of amplitude versus frequency are taken, one on the valve and the others (called background signatures) on pipes upstream and downstream of the valve. Background noise signatures are taken upstream and downstream of the valve to avoid errors due to erroneous measurements made by people and omissions of vital data. The differences between the signature on the valve and the background signatures indicate the presence or absence of a leak and its specific significance.

 For a leak-free valve, these differences must be small. The ratio in decibels at the dominant frequency (which is the frequency at which the amplitude has peak values), between the signature on the valve and those on the upstream side and the downstream side, represents the importance of the leak. Typically, the known apparatus implementing this method comprises a device for taking the acoustic signatures and for transferring these signatures onto graph paper with styles of different colors. The user must then manually determine the presence and the importance of the leak based on the signatures that have been drawn on the paper.

 The conventional method described above has the following disadvantages: First, it requires a large amount of paper. Secondly, since the device does not analyze the data, and neither the graph nor the graphs reveal the procedures for determining the presence and the importance of a leak, the conventional method requires a very important training of the user , many hours of work and an excessively large number of graphics.

SUMMARY OF THE INVENTION
The purpose of the invention is to provide:
an apparatus and method for automating the process of acoustically detecting leaks in valves carrying fluids;
an apparatus and a method of this kind eliminating the need to print acoustic signatures on paper;
an apparatus and method of this type which, to be used properly, does not require much training;
an apparatus and method of this kind which offer the advantages of eliminating large paper records and allowing for faster data collection, faster confirmation of reproducibility, more convenient data processing and analysis, integration of planning, recording, analysis, reporting and archiving, providing update and modification facilities through simple software changes, providing adaptability of the system to the specific needs of customers, and to reduce the need for training and know-how of staff to collect data;
- an apparatus and method of this kind offering the advantages of enabling collection, analysis and drawing of numerical conclusions, including a data collection unit and accessories including a FFT (Fast Fourier Transform) hardware module driven by software for converting the signals provided by the sensors into digital spectra that can be electronically transmitted to a computer and a software module for digital data collection and analysis in the factory; to enable the use of a desktop computer to develop and maintain valve system databases at the customer's premises; enable the use of a commercial desktop computer to develop standardized test procedures that allow for more detailed comparison and analysis of signatures, and the preparation of reports with minimal human intervention to maintain logging registers the history of the various valves installed in the customer's plant, and to allow customers to monitor test data and conclusions, but not to change them.

 a computer-based valve signature logging device comprising a programmed function button interface that guides the user through the organization, control and analysis of a valve leakage record, and a precise apparatus and arranged to handle multiple serial data relating to 500 or more valves, and a method of analyzing valves using such apparatus, which method automatically manipulates many of the operating details of instruments that may upset a user not familiar with electronics.

The invention therefore relates to an apparatus comprising sensor means for receiving acoustic signals from a valve system and for converting these acoustic signals into electrical signals; conversion means, such as conversion by transform of
Fast Fourier, adapted to receive electrical signals and transform these signals, by conversion such as Fast Fourier Transform conversion to produce acoustic signatures, and to output digital data representing the acoustic signatures; means for comparing at least two acoustic signatures to establish a recommended result for valve leaks; and digital means for storing digital data representing the acoustic signatures, and a conclusion or judgment derived from the digital data and the recommended result. The conclusion includes the user's assessment of the presence of a leak, the economic need for a repair and the quantification of the significance of the leak if present.

The invention also relates to a method which consists in associating several sensors to a valve system; to ensure that these sensors provide acoustic signals from the valve system and that these acoustic signals are converted into electrical signals, to convert them into a conversion
FFT or other conversion method for producing acoustic signatures and outputting digital data represent these acoustic signatures, comparing at least two of said acoustic signatures to establish a recommended result for valve leaks, and storing the data numerals representing the acoustic signatures and the conclusion or appreciation (as defined above) in a computer memory.

BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to the accompanying drawings, in which:
Figure 1 shows a general diagram of the apparatus according to the invention;
Figure 2 shows an "OK" sign in the user interface of the apparatus according to the invention;
Figure 3 shows a "YES / NO" sign in the user interface of the apparatus according to the invention;
Figure 4 shows a multiple choice panel in the user interface of the apparatus according to the invention;
Fig. 5 shows a digital panel in the user interface of the apparatus according to the invention;
Figure 6 shows an alphanumeric panel in the user interface of the apparatus according to the invention;
Figure 7 shows a CONTROL PANEL in the user interface of the apparatus according to the invention;
Fig. 8 shows a LIST PANEL in the user interface of the apparatus according to the invention;
Figure 9 shows a PANEL MAKING in the user interface of the apparatus according to the invention;
Fig. 10 shows a SIGNATURE PANEL in the user interface of the apparatus according to the invention;
Fig. 11 shows a CENSUS PANEL in the user interface of the apparatus according to the invention;
Fig. 12 shows a PANEL INFO in the user interface of the apparatus according to the invention;
FIG. 13 shows an ANALYSIS PANEL in the user interface of the apparatus according to the invention;
Fig. 14 shows a CONCLUSION PANEL in the user interface of the apparatus according to the invention;
Figure 15 shows the tree of use of the various panels in the user interface of the apparatus according to the invention;
Figure 16 shows the first part of an initialization flowchart of the apparatus and the operation of the CONTROL PANEL;
Figure 17 shows a flow diagram of the "SELECT ARTICLE"operation;
Fig. 18 shows the second part of the initialization flowchart of the apparatus and the operation of the CONTROL PANEL;
Fig. 19 shows a flowchart of the "LOAD ALL"operation;
Fig. 20 shows a flowchart of the operation of the LIST PANEL;
Figures 21 and 22 show a flowchart of the operation of the PANNEAU FAIRE;
Figs. 23, 24A, 24B, 25 and 26 show a flow diagram of the operation of the SIGNATURE PANEL;
Figures 27 and 28 show a flow diagram of the operation of the CENSUS PANEL;
Fig. 29 shows a flowchart of the operation of the INFO PANEL;
Figure 30 shows a flowchart of the operation
SAVE RESULTS in the INFO PANEL;
Figures 31 to 33 show a flowchart of the operation of the ANALYSIS PANEL;
Figure 34 shows a flowchart of the operation of the PANEL OF CONCLUSION; and
Figures 35 to 37 show a flowchart of the operation of a digital signal processor used in the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A system that is currently operational according to the invention will now be described with reference to the general diagram of FIG. 1. The apparatus 100 comprises two sensors, an A channel sensor 102 and a B channel sensor 104, for detecting the acoustic signals of the devices. valves.

The signals from these two sensors are sent to an FFT module 106 for transform conversion.
Fast Fourier or the like, in which they are analyzed by FFT to produce acoustic signatures. A central processing unit or CPU 108 controls the storage of these signatures on a hard disk 112 or any other storage device, the display of these signatures as well as the reception of user input signals, via a touch screen 110 or other similar user interface. The apparatus can exchange data with other devices through a port 114 for a floppy disk drive or the like. These components, as used in the present operational embodiment, will be described in detail below.

 The currently operational system is a battery-powered laptop computer equipped with data acquisition software, an FFT hardware module, spare batteries, sensors and other accessories, all of which are stowed in a strong case to allow use in the factory. A battery charger and a miniature printer can be supplied separately.

 The currently operational system measures 31.8 cm x 25 cm x 6.4 cm and weighs 4.5 kg. The system uses a 12 volt, 2.3 ampere-hour battery with lead and acid gel cells, with the possibility of quick exchange. An ON / OFF toggle switch on the right side of the system is the only external control on the system.

 The display measures 15.24 cm x 20.32 cm and uses a backlit liquid crystal display (LCD) with a video network of 640 x 480 pixels. A transparent pressure-sensitive film completely covers the LCD screen. Moderate finger pressure records "depression" and "looseness" with its horizontal and vertical coordinates, so activating a particular function on the LCD is a dedicated push-button on the system. Really constructed realization included a classic monitor and a mouse instead of a touch screen.

Those skilled in the art reading this description will be able to choose the appropriate user interface for a particular purpose.

 Two BNC connectors located at the top right of the system provide channel A and B channel inputs. Channel A input near the top is used for most applications. 100 kohm input impedance amplifiers are best suited for use with sensors for almost all valve signatures. Automatic gain control circuits, invisible to the user, replace the external attenuation or gain switch normally provided in other instruments.

The inputs of the channel A and channel B sensors are applied to the FFT module 106. This comprises an integrated circuit for performing the conversion by transform of
Fast Fourier of the signals received via the inputs of the sensors, under code control stored in an EEPROM memory or the like.

 The application program and the test data are stored on an internal hard disk of 80 Mbytes.

 Five connectors located on the left side of the system allow the system to be used as a 386SX compatible computer under DOS. The serial port (COM 1), external CRT monitor, and keyboard connectors are compatible with most available devices.

The floppy disk drive connector is not standard, but is designed to work with a 3 "drive powered by the internal battery.A tape drive can be used instead of the floppy disk drive, and such drives are available in the drive. trade and will not be described in detail here.

 The sensors are, for example, specially selected accelerometers for their response to acoustic emission signals in the frequency range of 10 kHz to 200 kHz. Paired pairs of two types of commercially available sensors are preferably used. When using sensors with the differential signature method, they must be factory matched.

 The preferred sensor is the most sensitive, particularly at frequencies around 25 kHz and can be used without a waveguide in a temperature range of -73 to +177 OC. It loses in sensitivity if the length of the cable exceeds 3 meters. Another type of usable sensor has a lower sensitivity of about 20 dB and it can be used to record signals exceeding the sensitivity of the instrument if they were recorded with preferred sensor. The second type of sensor has a temperature range of -73 to +177 ° C. It is the most sensitive at frequencies around or above 50 kHz, and can be used with cables up to 19 meters without losing signal strength.

 The choice of sensors depends on the circumstances, but once chosen, the same sensors, cables and waveguides must be used throughout the test.

Otherwise, the results of the various measurements can not be compared to determine if a valve is leaking.

 The sensor waveguide is a steel rod with a length of 200 mm and a diameter of 10 mm and at the end a sphere with a diameter of 12.5 mm. The other end has a thread for mounting the sensor by means of a mounting bracket 10-32.

 The sphere adapts to a hemispherical cell provided in the disk. A small amount of coupling resin should be applied to the transducer-rod interface and the sphere-disk interface to ensure good acoustic contact.

 The waveguide can be used as a hand probe to be able to move quickly from place to place or as a thermal insulator to protect the sensor and the user from high temperature valves and hoses.

 If you need to control valves on high temperature circuits, you should use the waveguide to prevent the sensors from overheating. These must not be heated beyond their temperature limit, because then they would be permanently damaged or destroyed. A small amount of coupling resin is needed on all metal-metal interfaces. No excessive pressure is required if the surfaces are free of dust and fit properly together. The end of the waveguide corresponding to the transducer must be held during the measurement.

 The sensor cables are coaxial, high temperature resistant cables with BNC connectors at one end and miniature coaxial connectors at the other end. Normally, a 5 meter cable is provided with each sensor. Other lengths are available.

 The software resides on the root directory of the hard drive mentioned above. Thus, it can be switched to higher power if desired, without the need to change the ROM chip or the like. The external floppy disk drive mentioned above can be used for this purpose.

 To allow a good understanding of the complex analysis software, we will first describe the main parts, then we will describe step by step the operation of the program. In the present description, the valves are grouped in the form of a plant, a unit, an article, a sub-article, a plan and a series. The unit is the highest group and typically represents the work of several days. An article is a particular assembly of test valves designated by an integer. Decimal numbers indicate sub-items (particularly valves or the like) .A plane is a test structure defined as a valve assembly or a modification of that assembly; a plane can represent one or more valves; less than one hundred shots can be used to cover almost all real situations. A series is a set of signatures for all the valves of an article. In one plane, any valve assembly can be defined as a system (for example a preheating system, a main steam system, an auxiliary steam system or an oil lubrication system). Parts of a system can still be called subsystems.

 The display and the touch screen form a flexible interface by function buttons to allow any interaction between the user and the instrument. Each function button is independently named and located in the touch area of the screen. In most cases, each function button is identified by a word or symbol surrounded by a rectangle the size of the fingertip. Exceptions are display and selection changes, which are located directly on a signature. Each time a button is activated, the rectangle will be highlighted until the button is released. If the finger pressure is released in the rectangle, the command or the appropriate character is recognized by the program. Then the display changes to show that selection. Typing the first letter of any button on the external keyboard also produces the same response. A mouse or other pointing device can also be used to activate the function buttons, if the work environment allows it.

 Function buttons can produce three types of response on the display. Many of them trigger an action that results in a visible change in their own display. Others produce a small window that requires only one answer per button, numeric or alphanumeric. The third type changes the entire display for a new panel. This window will contain another set of function buttons.

 The small decision windows, as shown in FIGS. 2 to 6, are used whenever the program requests the user to make an individual selection. There are five types of selection windows: the "OK" window (Figure 2), the "YES / NO" window (Figure 3), the multiple choice window (Figure 4), the numerical window (Figure 5), and the alphanumeric window (Figure 6). The "OK" window announces a particular situation and waits for the user to recognize it. The "YES / NO" window asks a specific question and waits for the user to press "YES" or "NO". The multiple choice window has a button for each allowed entry. After activating one of the entries, the window is removed. The numeric window asks the user to type a number. Among the buttons available in this window, "<" removes a number, "RET" sends the number to the program and removes the window and ESC cancels any entry and removes the window. A default selection is shown in parentheses. The alphanumeric window requires a name or comment.

Among the buttons available in this window, "<" removes a character, "RET" sends the command to the program and removes the window and "ESC" cancels the entry and removes the window. If the entry has already been started when this window appears, the previous entry is displayed and can be expanded or corrected.

 To simplify the organization and execution of a leak survey in multiple valves, the program divides the task as much as possible into manageable subtasks. The instrument displays only the functions required for the current task. This group of functions linked to a task on the screen is called a "task panel". The various task panels will be described with reference to Figures 7 to 14, which show the panels themselves, and Figure 15, which shows a tree for the use of these panels.

There are three levels of panels. The movement between the panels in the tree (Figure 15) is vertical. Operation always starts at the top of the
CONTROL PANEL 700 (Figure 7), go down, and go back up. A complete list of valve leaks includes preparation, valve testing, and reporting of results. The order in which the work is done is represented by the order of the panels from left to right: "LIST, MAKE THE PLAN,
SIGNATURES, and CENSUS, shown in Figures 8 to 11 and referenced 800 to 1100, respectively.

 The program starts automatically when the main switch is set to "on".

Initialization takes about two seconds. The unit, item, and plan are loaded from a previous status file so that the user has access to the previously used settings. The process is then from the top, namely the CONTROL PANEL.

 The CONTROL PANEL has two main purposes.

First, it defines the operating environment of the current test. Secondly, it provides the function buttons 702 to 710 to direct the user to one of the four second level panels, namely: "LIST", "MAKE A PLAN", "SIGNATURES" and "CENSUS", or to the "EXIT" command, to exit the analysis operation, respectively.

 All operating data is listed under the \ UNITE directory. The use of this directory allows the survey work to progress on two or more independent groups of valves without having to clear and reload for each one of them. As will be appreciated by those skilled in the art, valve clustering can be done at any desired level, such as factory, unit, system or subsystem level.

 The UNITE button 712 is used to select the name of the unit, the latter being used as a directory on the hard disk; in the DOS tree, this directory is located directly under "\ UNITE". This entry is rarely changed. The work of a unit usually covers many days. By pressing this button, the panel shows a list of already established units. The previously activated unit is highlighted. The user touches the name of the desired unit. It will follow the loading of the articles, and the CONTROL PANEL reappears to display the results of the loading of the articles.

 The correct unit must be checked each time at the top of the CONTROL PANEL. An inaccurate selection can waste a lot of work by using the wrong list and bad plans and mixing the signatures with that of another unit.

 The ARTICLE 714 button brings up a numeric panel to choose the next fundamental item.

The default neighbor item (in the list) is shown in parentheses. After choosing a number, the series is reset to zero. If the article is chosen for the first time, the subdirectory of the basic article is created. Then the loading sequence is executed.

 The PLAN 716 button shows the available plans in the particular unit. Most plan selections should be made while preparing the valve list and then designing any new plans. The previous active plan is highlighted. The user chooses the desired plan. If a change of plan is accepted, the program reloads the signatures of the basic article.

 In the example illustrated in the figure, the plan 20 which comprises five valves, in the form of the connection diagram 701, has been shown. In table 724 in the lower right corner, items .0 to .4 have been shown. "X" designates the closure, the "O" the opening and the "T" the automatic purge for each step from 1 to 4. In this notation, the parentheses indicate that a valve is under pressure, the slashes indicating that a valve is not under pressure, the "d" indicating that a differential signature (described below) is required for this valve.

 The SERIE 718 button brings up the numeric panel to accept the input of a serial number from 0 to 15. The highest series with signatures has been shown. The user enters a number between 0 and 15. If this number is one unit higher than the highest series used, it will be reduced to prevent a series from being skipped. If a valid change of series is accepted, the program reloads the signatures of the basic article.

 On the SERIE button, the serial word is written as "XERIES" so that the user can choose either the serial button or the signature button by typing the first letter. Other conventions can of course be used to achieve the same goal. As shown, the current series is series number 0. Series number 1 has a separate set of signatures and may involve a different test, for example after repair rather than before.

 Only the signatures saved under the chosen series will appear as saved. The user should not misunderstand an incorrect series due to a situation involving missing signatures.

 The FREQUENCY button 720 allows to choose a range of frequencies, 200 kHz being the standard range used for the leakage signatures of a valve. Activating this button immediately changes the frequency to the next available selection such as 100/200/400/800 kHz. Under each setting, each signature displayed and saved covers between 10% and 100% of the frequency range.

The frequency is automatically set when the signatures are loaded. The frequency can not be changed after at least one signature has been saved in a series. The frequency can be changed by advancing to the next series.

 The AVERAGE button 722 is used to select the "average" variable. The variable "average" has two objectives.

The standard signature display represented by amplitude vs. frequency, uses the "average" as the time in seconds that the device averages the signature, each time the "EXECUTE" button is enabled . Mean = 0 means that only one reading is used for signing. By pressing this button, the value alternates between 0.1 and 2.

The second objective of this variable is to allow the setting of the displayed duration in the case of a time-scanning signature (the amplitude as a function of time).

 The LIST, FAIRE, SIGNATURE and CENSUS buttons 702 to 708 respectively allow the LIST, FAIRE, SIGNATURE and CENSUS panels to be analyzed, these operations being explained below. The use of the SIGNATURE 706 button assumes that the fundamental item, plan, series, frequency band and average have been chosen.

 The EXIT 710 button terminates the program. The computer goes back to DOS and can be turned off by the power switch.

 Each time the item, plan, or series is changed, the program automatically engages in the next sequence. He (1) searches on the hard drive for the subdirectory of the basic article and (2) loads any already saved signature that corresponds to the chosen plan and series. The signatures already saved are marked with an "*" in the plan.

The loading of the signatures can lead to one of the following error messages:
"ERROR: Plan 1 already used, use it again"?
If all signatures are saved under a different plan, this plan can be used again by answering "YES" to this question.

 "Warning: Several shots used". This message will appear, if some signatures have been saved under a different plan.

 "Signatures do not match". This message indicates that if the plan has been changed, the signatures that were saved do not match the entry in that plan.

 "The last signatures were taken in series 1". If higher series signatures have been saved, the highest series taken will be rated to help prevent a mix of new signatures with the old series.

The LIST PANEL 800 is a means for querying the list of valves and displayed items corresponding to any chosen set of criteria. The valve list is an ordered database comprising information categories (fields) such as item, plan and identification information and is organized as a hierarchical data structure and relational. First, the user enters an entry in any number of fields of the search definition line 802. When the desired criterion has been entered, the user presses the button
QUERY 804 to trigger the search and display of results. Finally, the user selects the desired article for collection and analysis by pointing to the article. The article will be displayed at the top of the screen.

The user presses the TEST-IT 806 button to return to the CONTROL PANEL with the selected item.

 All fields except two use an alphanumeric text search. The keyword can be any combination of letters, numbers, and even punctuation characters, but no spaces. The allowed length is the size of the displayed field. Equality requires that the entire keyword be found anywhere in the corresponding field of a particular item.

 Only the item and elevation fields use a search with upper / lower numerical limit. The operator must enter both the upper and lower limits to search through these fields. Equality requires that the corresponding field entry for a particular item be between the selected upper / lower limits.

 To enter a search criterion in a particular field, the user points to that field in the search definition box (rows 2-5).

Activation of the 805 button causes the highlighting of the numeric or alphanumeric window. The operator then enters the desired word (or number) and presses the key
RETURN. By pressing the RETURN button if there is no entry, any search criteria is removed from this field. The ESC 816 button ignores any input changes.

 An example of a general search is an entry only in the elevation field to assist in ordering the reading of all valves.

 The QUERY button initializes a search of the valve list. Each item in the list is taken field by field and is rejected if the field keyword is not found in the corresponding field of this article. It is only when all fields match the search criteria that the item is displayed in the list found.

 A general search can return many items to the list found. These will be separated into two sections with a dotted line between them. Items above the dotted line are not yet tested, while items below the line have already been concluded. Therefore, as the LIST PANEL is used repeatedly during a survey with constant search criteria, the items will be selected in the top section for collection and analysis, and then appear in the list. the bottom section.

 To choose an article, the user points to the number of the article. The user examines the highlighted line of the article to verify that the article corresponds to his choice. If this is not the case, the user simply points to another article or redefines the search to produce a different list of found articles.

After a particular item has been identified (the line is highlighted), the TEST-IT button will take the number of that item and return to the PANEL.
COMMAND, as if the user had pressed the ARTICLE button and typed this number. He can then go to
PANEL OF SIGNATURES.

The ESC button is used to return to the PANEL OF
ORDER without change of article.

 The up and down arrows move the cursor of the search definition region through the list found. The left and right arrows move the cursor horizontally only in the search definition region.

 The FAIRE 900 panel provides all the tools necessary to prepare a plan for testing any fundamental article and its associated sub-articles.

The instrument imposes no constraints on the design of the plan other than a maximum of 15 valves and 15 steps (rows and columns). The number of sub-items in a plan can not be less than the number of
LIST PANEL. The instrument automatically enters the optimal input X (closed) or O (open), to the left of each signature entry, (X) or / O / or / X / or Xd.

In this notation, the parentheses indicate that the valve is under pressure, the slashes indicating that the valve is not under pressure, while the "d" indicates that a differential signature is taken for this valve. The "T" indicates a signature of the amplitude as a function of time. Some buttons have a dual function to prepare the plan depending on whether a valve or piping has been selected and highlighted first. These differences in objectives will be explained in more detail below.

 The VALVES 902 button is enabled to perform the following functions of the PANEL: They include all operations related to the plan and the valves highlighted in the connection diagram.

A valve of the diagram will be highlighted.

 To enter an entry in the map table instead of the cursor, the user presses one of the buttons 904, namely X, O, (X), / O /, / X /, Xd, and T. If the cursor is on a sub-article, or on a stage, nothing happens. The various valves in the plane are indicated by decimal digits, the one indicated by .0 being the most important.

Activating the MOVE button 906 moves the highlighted valve in the connection diagram. The arrows are then activated to move the valve to the desired location; then, the user presses the ESC 908 button. The other buttons do not work while the MOVE operation is in progress (button
MOVE highlighted).

 If the clip cursor points to a sub-item, and there are fewer than 15 sub-items in the clip, a new line of sub-items will be created in the clip when the INSERT 910 button is activated. If a sub item line has been deleted previously, it will automatically fill in this inserted line. If the cursor is on a step digit and there are fewer than 15 steps, a new step column will be opened.

 If the clip cursor is on a sub-item when the CLEAR 912 button is on, the whole line of that sub-item will be erased, and the lines below will move up. An insert can be used to restore an incorrectly deleted sub-item line. If the cursor is on a step number, this step column will be erased and any column on the right will shift.

 The four arrow buttons 914 move the clip cursor in it. If the cursor is on a step number at the top of the clip, moving to the right beyond the last step will add another step up to a maximum of 15. If the cursor is on a subarticle number to the left of the clip , the descent below the last sub-item will add another sub-item up to a maximum of 15. If the cursor is on a sub-item number to the left of the shot, pressing the left arrow makes appear the alphanumeric panel requesting the entry of a description of the valve of the plane. It should be noted that the plane will scroll horizontally and vertically to fit the limited dimension of the display, and that the valve highlighted in the connection diagram will follow the trace of the sub-item on which the cursor of plan .

The PIPE 916 button allows the buttons to move,
INSERT and CLEAR to assume their secondary functions to operate on piping sections in the connection diagram. In this case, a pipe will be highlighted in the diagram. These secondary functions will now be described.

 By pressing the MOVE button, you can move the highlighted pipe in the connection diagram.

Then, activate the arrow buttons to move the pipe to the desired location and finally the user presses ESC when finished. No other button works when the MOVE operation is in progress (button
MOVE highlighted).

 After pressing the INSERT button to insert a pipe, an arrow button must be activated to determine the pipe orientation, horizontal or vertical. The highlighted pipe appears on the right of the diagram. Then, the arrow buttons are used to place it as in the MOVE operation and finally the user activates the ESC button as soon as it is finished.

 When the CLEAR button is activated, the highlighted pipe, if any, in the connection diagram will be erased.

 The arrow buttons are used to move highlighting among the pipe elements to choose the section of pipe to move or erase.

When the design of the plan is complete, the button
SAVE 918 is enabled to save the plan to the hard drive. First, the display makes a list of available plans in the current unit. Then, it brings up the alphanumeric panel to accept a name entry. Name entries can be any unique combination up to four characters (frequently the names are only serial numbers for easy archiving). If the name chosen is already used, the
PANEL YES / NO requests a check to rewrite this plan. After saving the plane, the device or analyzer leaves the PANEL and returns to the PANEL.
CONTROL.

When the ESC button is on, the analyzer leaves the PANEL and returns to the CONTROL PANEL. If changes have been made, a YES / NO PANEL will ask for a rewriting confirmation of the plan in the form saved last, after which we return to the PANEL.
CONTROL.

 The purpose of the plan is to provide an organized structure for testing and analyzing a particular group of valves. Most valve groups correspond to a pre-tested and optimized standard plan, which allows the PANEL to be reserved for the preparation of a group of non-standard valves or to restructure the test under restricted access conditions.

 The remaining panels are used for control and analysis of the valves. Their use will now be described.

One of the most important functions of the analyzer is the semi-automatic process of collecting signatures. The SIGNATURE PANEL 1000 shown in Fig. 10, leads the user through each pressure signature and each background noise signature recommended in the connection diagram 1001 and the plan table 1003. This process follows the collection cycle of all signatures during a step to then move to the right in the plan table to the next step. A step column in the plan table represents all items (valves) having the condition indicated, as well as the type of signature to be collected for each item. Referring to FIG.
X represents a closed valve;
O represents an open valve;
(X) represents a signature of the pressure amplitude of the closed valve as a function of frequency;
/ 0 / represents a noise amplitude signature of an open valve as a function of frequency;
/ X / represents the background noise amplitude of an open valve as a function of frequency
Xd represents a signature of the pressure amplitude of a closed valve as a function of frequency, as well as two signatures of background noise amplitude as a function of frequency;
(T) represents a valve pressure amplitude signature closed as a function of time; and
/ T / represents an amplitude signature of background noise as a function of time, either for a closed valve or for an open valve.

 Moving to a different step in the plane requires changing the condition of one or more valves (and thus changing the pressure by opening or closing one or more valves in a plane). The automatic collection process collects pressure signatures and background signatures on all valves to be tested, with minimal opening and closing of the valves. Normally, it begins with the highlighting of the first valve and the first step of the plane. As illustrated in step 1, the valve .0 is closed and the valves 2, 3 and 4 are open. If they are not already in this position, the operator must open them or close them correspondingly to satisfy the imposed condition. Then a time signature is taken by pressing EXECUTION and then SAVE. The other steps take place in a similar way.

If beginner operation is chosen, a valve alignment procedure is displayed at initialization and each time the cursor is moved from one step to another. A YES / NO PANEL indicates each valve and the position of the valve that the user must choose. If all indications in the current step are answered "YES", the analyzer continues normally. If there is an answer "NO" the indications of choice for this step are stopped, but a warning will appear each time the button
EXECUTION is enabled.

 The instrument advances the cursor to the first signature during the current step and then displays a message indicating that the sensor should be placed on the indicated valve and the EXECUTION button pressed.

 When the user presses the EXECUTION button, the instrument responds with a message prompting to press the EXECUTION button again until the reproducibility check requirement is satisfied (as described below). When the reproducibility requirement is satisfied, the instrument prompts the user to press the SAVE button. Then the user touches the SAVE button. The instrument then advances the cursor to the next signature in this step and the above process is repeated for each signature in this step. The instrument then advances the cursor to the next step and returns to the valve alignment procedure described above.

 A signature can be collected for each element (X), / O /, / X /, (T) and / T / in the plane. A differential element Xd requires three signatures. For their collection, each time the cursor is on an XD, an additional group of buttons 1002 is highlighted just above the plan table. This group of buttons defaults to the form shown for single-sensor differential analysis.

 In this case the instrument will prompt the user to set the sensor to press EXECUTE and SAVE for each of the three locations, as described above. If the user wishes to perform a two-sensor differential analysis, he / she must press the MODE button, which results in buttons for the two-sensor differential analysis being displayed. In this case, the instrument prompts the user to place two sensors in appropriate locations rather than one, so that two signatures can be collected simultaneously.

 The EXECUTION-SAVE routine is implemented for each location, by manually activating either the VALVE button, or one of the three buttons 1002, or by letting the instrument advance automatically.

The asterisk * in the plan table indicates that the valve signature of an Xd group has been saved, while the rescue of the upstream and downstream signatures is indicated saved by the sign (*) on the corresponding buttons .

The apparent size of the signatures displayed in the SIGNATURE PANEL is set by the selected attenuation (ATTEN). To shrink the display, the user can point anywhere in the bottom half of the signature box. To magnify display details, the user can point to the display anywhere in the top half of the box. The attenuation changes in steps of 5 dB between -10 and 60 dB. A change of 5 dB corresponds to a magnification of 1.78, while 60 dB indicates a magnification of 1.000. The absolute amplitudes of the signal are determined by adding the value
ATTEN to the approximate number of dB of the peak as read on the left side of the signature. In the PANEL
SIGNATURES shown in Figure 10, the attenuation is set to 35 dB.

 The MODE 1004 button goes through the available modes for a given clip element. The MODE button changes the function of the BW 1006 button, whose use will now be described.

 In A, B, and A-B modes, the MODE button changes the smoothing bandwidth of the display from 1% to 3% of the frequency range. In the time scan mode, the display shows the amplitude as a function of time. This amplitude is an average over a fixed frequency band having a width of 10% of the frequency range. When the BW button is on, the display switches to a frequency signature based on the frequency. The sensor is placed on a trap (a certain type of valve as experts know) and it points anywhere on the screen to read a signature.

Then, the center frequency of the sweep is chosen by pointing to the signature at an appropriate region of the high signal. The dark bar under the signature indicates the frequency band on which the average is to be made. The ESC 1008 button is activated when the selected band is correct. The display will return to the time scan mode with the selected center frequency displayed below the BW button.

 The CLR 1010 button removes any signature already started by EXECUTION but not yet saved, which allows the EXECUTION procedure to be repeated. This is used each time the initial EXECUTION command for a valve produces a non-reproducible signature because the sensor has been improperly applied to the valve.

The EXECUTION 1012 button begins the execution operation which is the central function of the entire instrument. The most important time is spent actually testing the valves. Whenever the clip cursor highlights a type of signature ie (X), / O /, / X /, Xd, or T, one of the following messages is displayed under the CLR and EXECUTION buttons and the button
EXECUTION can be activated:
"Place the sensor on item 1.0 and press the EXECUTION button". When the EXECUTION button is activated, the instrument acquires and displays the signature, unless one of the following messages appears: "No
Stable ";" Resume "or" Check ":" Replace sensor on valve 1.0 and press EXECUTE ".

 "Good reproducibility, press SAVE".

 All elements in the plane except the T (time scan) use a reproducibility test that requires more than one activation of the EXECUTION button.

The initial EXECUTION action for a particular element of the plan displays a signature with a solid line. Each subsequent EXECUTION action displays a signature with a dotted line that is used only for reproducibility control. If this check is satisfactory, a SAVE action is requested. If it is not satisfactory, the verification message is repeated.

If the initial signature is not good (it can not be repeated), the CLR button must be enabled to resume an initial signature.

 For a time scan, the EXECUTION action triggers a slow amplitude sweep as a function of time (see BW). The length depends on the average setting on the CONTROL PANEL. Time-stamped signatures do not require reproducibility checking because they depend essentially on time.

The SAVE action is requested when the function is complete.

 If the current element already has a saved signature, indicated by * in the plan, it will be noted as saved on the signature and displayed by a solid line until the EXECUTION action acquires a new signature.

Each signature must be saved by the user to save for subsequent analysis by pressing the SAVE button after an EXECUTION action has produced a reproducible signature. The solid line (reading of the initial EXECUTION action) on the display will be stored on the hard disk under the appropriate file name. The SAVE function can produce one of the following messages:
"Not stable, save anyway?" If the function
EXECUTION can not produce a reproducible signature, a SAVE action can be executed by answering YES to this question.

 "This series has saved data, do you want to replace them?" If a previous signature has been saved under this sub-item and this step, this "YES / NO" window will ask for confirmation of replacement.

 "Do you want to save the next series?" If you do not want a replacement, (avoid losing the previous signature), then a YES answer to this window automatically advances to the next series. The plan shows the saved status of all the signatures of the new series. The number of the series is printed just above the plane.

 If a signature is already saved at the sub-item and at the current step, the CLEAR button 1014 will ask for confirmation by YES / NO and then clears the signature of the hard drive. This is used if the user does not want to rewrite on a badly taken signature.

 The SAVE button also automatically advances across the plane to the next signature not yet completed. First, it checks the next signature element to complete the current step. If no other signatures are needed, the cursor moves to the next step, follows the valve alignment enhancement procedure and continues to check this step, as above. If all signatures are completed, the message "PLAN COMPLETED" is displayed.

The INFO 1016 button switches the device to the
INFO PANEL.

The ANALYZER 1018 button switches the device to the
PANEL ANALYSIS. This is commonly used after filling the plan with as many signatures as required to obtain a recommended result and / or to draw a conclusion. The ANALYZE function should not be used immediately after taking signatures on items in a particular plan. A fundamental article can be chosen again in the PANEL OF
COMMAND and you can access this function anytime.

The ESC 1008 button switches the analyzer to the PANEL
CONTROL.

 The LEFT / RIGHT ARROW buttons 1020 above the plane move the slider between plan steps. If the signature elements in this step have not been saved, a warning will appear. If beginner mode is enabled, the alignment check is performed each time.

 The UP / DOWN arrow buttons 1022 below the plane move the plane cursor between the valves (sub-items) of the plane.

 The valve connection diagram shows both the position of the valve on which the cursor is pointing and the state of each valve at the step highlighted by the cursor in the plane. The closed valves (ie the elements X, (X), / X / or Xd) are written in the diagram. The open valves (ie the elements O or / O /) are not written in the diagram.

 CENSUS 1100 in Figure 11 provides an overview of the completion of the survey and provides outputs for sending to other databases.

 The initial panel includes all the basic item numbers for which signatures have been made. If results have been recorded, the last date will be displayed next to the item number.

The REV ART 1102 button (item count) displays the numeric panel to enter an item number. If the RET button is enabled, the display returns to the CONTROL PANEL, then to the
PANEL OF SIGNATURES using the entered article. A more direct way to do this is to simply point to the item number on the screen.

 The SHOW COMPLETE LIST 1104 button is enabled to see a complete list of signatures, results, and completed comments. Those represented only concern the first series. First, on the left, we find the article number, followed by columns of plan elements, each element of the plan representing a single signature completed. These items are displayed as in the plan table except items that have not been completed and items that do not require a signature that are not shown. The next column is marked if signatures have been taken on an additional series. This is followed by the results and then by the comments that have been entered.

 When the OUTPUTS 1106 button is enabled, all results and comments are compiled into a file called RESULTS.CMP. This data can be imported directly into PARADOX for reporting.

When the COMPRESSION 1108 button is enabled, all the job related to a unit is compiled into a single file to allow backup. This involves the LIST OF VALVES, PLANS, SIGNATURES, RESULTS and
INFORMATION. The file name is <Unit> .EXE. This file is a self-extracting archive, as those who know the archive files know it. After saving using the COMPRESSION button, the user can exit the program and then use the command
DOS COPY to copy this file to a 3.5-inch floppy disk. The use of such a 3.5 inch floppy disk is only given as an example, other storage media can be used depending on the circumstances.

The recovery on another computer can be made by creating the appropriate directory for the UNITE, the compiled file being copied by typing the name of the UNITE:
<UNITE> / d / o <UNITE> is the name of the unit containing the statement. For example, if the name of the unit is LEB2, the self-extracting archive file will be named LEB2.EXE, and the command to retrieve the data will be LEB2 / d / o.

The ESC 1110 button returns the display to the
CONTROL PANEL.

 Figure 12 shows the INFO PANEL 1200. As can be seen in this figure, this panel allows the display and entry of information about each valve.

 Figure 13 shows the ANALYSIS PANEL 1300. By comparing the signatures, the user can determine the existence and the importance of the leaks by the differential signature method described above. As described below, it is also possible to automate the determination of the dominant frequency and thus automate the comparison of signatures to obtain a recommended result that the user can accept or reject as a conclusion.

 Figure 14 shows CONCLUSION BOARD 1400.

In this panel, column 1402 identifies each item.

Column 1404 identifies the result for each item, where L = leak, L2 = likely leak, T = leak,
T2 = probably tight, NA = not retained, and NT = not tested. Note that the PANEL OF CONCLUSION is a visual representation of the analysis performed by the apparatus of the invention. The analysis is considered a recommended result. An operator can draw a conclusion from the displayed result and accept or override it. Whatever the decision made by the user, it is decisive and naturally established after an evaluation of the recommended result. The conclusion of the operator can be entered by means of
MULTIPLE CHOICE PANEL 1410. Column 1406 gives the estimated importance of each leak, small, medium or large. Column 1408 allows the user to enter free text reflecting their comments on each valve.

 After describing the user interface, the procedures followed by the software controlling the apparatus will now be described with reference to the flowcharts of FIGS. 16 to 34. Some of these procedures may be implemented in specially designed software. dedicated to these tasks such as PARADOXALE for data management, EXCELX or QUATTRO PRO for numerical analysis, and WORD for the preparation of reports.

 The operation of the apparatus, from its start up to the choice of one of the four panels located directly below the CONTROL PANEL, is shown in the flowchart of Figures 16 to 18. When the apparatus is started (step 1602), the status file is loaded (step 1604), and the article is selected by the SELECT ARTICLE operation (step 1608 described in detail hereinafter with reference to FIG. 17).

The user can then choose a number of units (steps 1610 to 1616), in which case the item number is set to 1 by default (step 1618), or he can choose an item number (steps 1620 to 1616). 1624), in which case the serial number is set to 0 by default (step 1626).

In either case, the SELECT ARTICLE operation begins again (step 1628). The user can also choose a plan (steps 1630 to 1636) or a series (steps 1638 to 1644). In either case, the LOAD ALL operation begins (step 1646 described in more detail below with reference to FIG. 19). When the CHOOSE ARTICLE or LOAD ALL operation is finished, the user is taken back to the CONTROL PANEL.

The user can also choose a frequency (steps 1802 to 1810) or an average (steps 1812 to 1820).

The user can also press EXIT (step 1822), in which case he exits the program (step 1824). All of these procedures except EXIT being performed, the user can go to the LIST PANEL (steps 1826 and 1828),
PANEL (steps 1830 and 1832), at the PANEL OF
SIGNATURES (Steps 1834 and 1836), or at the PANEL
CENSUS (Steps 1838 and 1840).

 The SELECT ARTICLE operation will now be described with reference to FIG. 17. When this operation is called (step 1702), it is checked whether the selected number of the item is part of the list (step 1704). If it is not, the previous article is retained (step 1714) and the command returns to the operation that called the SELECT ARTICLE operation (step 1716). If the chosen number of the article is part of the list, the article is confirmed (step 1706), the valve information is loaded (step 1708), the list plan is confirmed (step 1710), and the LOAD ALL operation is started (step 1712). When the LOAD ALL operation is finished, the command returns to the operation that called the SELECT OBJECT operation.

 The LOAD ALL operation will now be described with reference to Fig. 19. When this operation is called (step 1902), all the subarticles in the plane are loaded with the valve conclusions and the external conditions (step 1904), and the unit / article directory is searched (step 1906). Each file name is checked to see if it designates a signature file, and the highest set of signatures is maintained (steps 1908-1912). If the file is not the correct series, and if there are more files, the search continues (steps 1914 and 1936), and if the chosen series is too high, the series is reset (steps 1938 and 1940) If the file is the correct series, it is read to see if the signature needs to be loaded into the plan or if there is a signature error (steps 1916 to 1934), and steps 1936, 1938, and as needed step 1940 are executed again. If the chosen series is not too high, the plan is checked (steps 1944 to 1960), and the command is returned to the operation that called the LOAD ALL operation (step 1962). The program may also load a plan (step 1942) if no plan is selected or if a different plan has been used.

 The operation of the LIST PANEL will be described with reference to Figure 20. When this panel is called (step 2002), it is displayed (step 2004), the last search definition is displayed (step 2006) and the work item is displayed (step 2008). Then, the user can define a search (steps 2010 to 2022), perform a search (steps 2024 to 2036), choose the work item (step 2038), and then press TESTER to use the selected item (steps 2040). and 2042) or ESC to retain the previous article (steps 2044 and 2046). Then, the user is taken back to the CONTROL PANEL (step 2048).

The operation of the PANEL will be described with reference to FIGS. 21 and 22. When this panel is called (step 2102), it is displayed (step 2104)
The user can then move valves or pipes (steps 2106 to 2114), insert piping (steps 2120, 2122, 2116 and 2118), insert valves (steps 2120 to 2136), remove from the piping (steps 2138 to 2142), removing valves (steps 2138, 2140 and 2144 to 2154), making inputs (steps 2202 to 2206), using the arrow buttons to move the cursor to a specific pipe section or valve (steps 2208 to 2216) ), or choose the PIPE or VALVE mode (steps 2218 to 2228). Then, the user saves the plan (steps 22302232) or presses ESC to restore the previous plan (steps 2234 to 2236); in all cases, the user is returned to the CONTROL PANEL (step 2238).

 The operation of the SIGNATURE PANEL will be described with reference to Figures 23, 24A, 24B, 25 and 26.

When this panel is called (step 2302), it is displayed (step 2304). It is determined whether there is a signature entry by the cursor in the plane (step 2306). If so, it is determined whether the signature has already been saved (and marked in the plan with an asterisk) (step 2308). According to this determination, the user is guided through the signature taking steps (steps 2310 to 2314), or the saved signature is displayed (step 2316).

When the BW button is turned on (step 2318), the signature input type is determined (step 2320). If the signature is a frequency signature, the user has the option of switching the smoothing of the display between 1% and 3% (step 2322). If the signature is a time signature, several options are provided for displaying the frequency signature (steps 2324 to 2338).

 When the EXECUTION button is activated (step 2402), the user is guided through the steps of collecting a frequency signature (steps 2408 to 2452) or a time signature (steps 2454 to 2466).

 An important function of the SIGNATURE PANEL is the determination of the reproducibility of the taking of signatures. The measurement of the acoustic noise of the valve by a sensor depends on a good coupling of the noise with the sensor. Although it is impossible to verify the maximum coupling with 100% certainty, experience has shown that the maximum achievable coupling for a particular valve is reproducible with a rate better than a dB. This achievable signal is then a function of the contact force of the sensor, the angle, and the coupling resin used. Sensitivity to each of these conditions may involve a level change of more than 60 dB. So, the only condition that produces a stable level, assuming the control is manual, is the maximum achievable coupling.

The operation of the SIGNATURE PANEL automatically performs the following reproducibility measurement on each collection of signatures, while providing the user with the necessary messages for executing his commands:
1. The user places the sensor on the valve and presses the EXECUTION button (step 2402). The first signature produced for a valve is displayed by a solid line S1 (step 2448).

 2. The user lifts the sensor and places it back on the valve and presses EXECUTION again.

This second signature is displayed by a dashed line S2 (step 2430).

3. The system does the following calculation:

<tb> Reproducibility <SEP> = <SEP> (Sl (f) - <SEP> 52 (f)) <SEP> / <SEP> S (IF (f))
<tb> where Sl (f) is the amplitude versus frequency and z is the sum over 10% to 100% of the frequency range of the signature (step 2436).

 4. The user returns to step 2 to take another signature S2 and compare it to S1 if the reproducibility is not less than 10% (1 dB) (step 2446).

 If the reproducibility is less than 10% (ldB), the signature is good. Otherwise, the user returns to step 2 or 3 according to the message (which depends on the second-level reproducibility). This reproducibility criterion is adjustable. Previous processes required human judgment, which varied from user to user.

 The second level of reproducibility control is a test (non-determinant) of the variation of the signature over time, while the sensor is held in place. Each time the EXECUTION button is activated, two or three signatures are taken quickly.

If they are not repeated with the same criteria as above, the highest one is retained, but it is marked as unstable.

 Reproducibility will be good only if the first signature was stable. If this is not the case, the cause is either a poor coupling of the sensor to S1, or a system instability (background noise or parasitic pressure). An appropriate message is displayed leading the user to a good signature or a conclusion of instability varying with time. In this case, a differential signature or a signature as a function of time may lead to a conclusion.

Each time a signature is displayed, the user can change the attenuation by pointing to the upper or lower half of the signature (steps 2468 to 2480). After collecting a signature by pressing the EXECUTION button, the user can choose to save the signature (steps 2502 to 2524), or to delete it (steps 2526 to 2542). If the user needs to skip some signatures or stil needs to take them in a different order, he can use the arrow buttons to move the cursor to an item and / or a different step in the plan (steps 2610-2626) . In addition, the user can choose the INFO PANEL (steps 2602 and 2604) or choose the ANALYTICAL PANEL (steps 2606 and 2608), or else he can choose the button
ESC to return to the CONTROL PANEL (steps 2628 and 2634).

The operation of the CENSING PANEL will be described with reference to Figs. 27 and 28. When this panel is selected (step 2702), it is displayed (step 2704). It is possible to review an article by its number (steps 2706 to 2716) or to have a list of all articles (steps 2718 to 2748). It is also possible to transfer the information to an output (steps 2802 to 2814), to compress the unit into an archive self-extracting file as described above (steps 2816 and 2818), or to press the ESC button to return to
CONTROL PANEL (Steps 2820 and 2822).

The operation of the INFO PANEL will be described with reference to FIG. 29. When this panel is selected (step 2902), it is displayed including the valve information, the result table, and the marked external conditions (step 2904). At this moment, the PANEL
CONCLUSION may be selected (steps 2906 and 2908), or the user may proceed to the next sub-article, if there is one (steps 2910-2916). The arrow buttons can be used to move the cursor to a different series in the result table (steps 2918 and 2920). When the EXTERNAL CONDITIONS button is enabled, (step 2922), the external pointer is moved to the indicated field (step 2924), and an external condition marker is set or deleted (step 2926). When the ESC button is activated (step 2928), the results are saved (step 2930) - the saving of the results will be explained below with reference to Fig. 30 -, and the operation returns to the CONTROL PANEL (step 2932).

 The operation of the save operation of the results will be explained with reference to Figure 30.

When this operation is called (step 3002), it is determined if changes in the results have occurred (step 3004), and if so, the user is asked if he wants to save them (step 3008) . If there are no changes in the results, or if the user chooses not to save them, the command is returned to the previous operation (step 3006). If the user chooses to save the result changes, each sub-item is saved in turn (step 3010-3016), and the command is returned to the previous operation (step 3018).

 The operation of the ANALYSIS PANEL will be described with reference to FIGS. 31 to 33. When this panel is called (step 3102), it is determined whether the cursor is on a differential signature (step 3104). If this is the case, the procedure in Figure 33 will be followed, as explained below. Otherwise, the signatures to be displayed are marked according to the position of the cursor in the plane (step 3106), and the ANALYSIS PANEL is displayed (step 3108). The user can select items with the "up" arrow (steps 3110 through 3118) or with the "down" arrow (steps 3120 through 3130) or he can switch to the RESULTS PANEL (steps 3132 and 3134) .

When the SELECTION button is activated (step 3202), the user can choose a sub-item with the numeric keypad (steps 3204 to 3212). With the DIF button, the user can display the difference between any two signatures in a third box (steps 3214 to 3218). The INFO button calls the INFO PANEL (steps 3220 and 3222). The arrows "to the left" and "to the right" move the signatures to view other steps of the plane (steps 3224 and 3226). The button
ESC saves the results and returns to the PANEL OF
CONTROL (steps 3228 to 3232).

The operation of the ANALYSIS PANEL in the case of a differential signature will be explained with reference to Figure 33. In this case, the signatures upstream, of the valve, and downstream are displayed on the first line while the signatures Differential valves less upstream and less downstream valve are displayed on the middle line (step 3302). The user can then switch to the CONCLUSION PANEL (steps 3304 and 3306) or choose a sub-item and a step with the numeric keypad (steps 3308 to 3318), in which case the selected signatures are displayed on the last line (step 3320). ). The user can also press the button
ESC to return to the CONTROL PANEL (steps 3322 to 3326).

METHODS OF COMPARING SIGNATURES
The software performs the valve leak analysis by a comparison of the signatures. The analysis of valve leaks is usually a complex problem.

Three questions must be resolved. First, the noise due to a leak has a considerable and determinable coupling between the valves in a system.

Secondly, multiple sources of noise must be identified. Third, external sources of background noise (eg, pumps and condensers) can mask the noise due to leakage. Therefore, there are cases where valve position changes (openings or closures) are not sufficient or possible to positively identify the sources and the significance of the leaks. In these cases the following differential methods are used.

 Differential methods make automatic the general method of comparing signatures. They consist of subtracting one signature from another on a single display to give a better visual resolution of the comparison of amplitudes, and to eliminate human errors from previous manual processes. The user analysis and also the automatic analysis then take into account the noise coupling function as follows. Noise is attenuated as it travels along one pipe from one valve to the next. This coupling is a function of the frequency, the attenuation at a certain frequency being given in dB per unit of length expressed in units of pipe diameter. This attenuation increases approximately with the square root of the frequency. For example, the attenuation between two valves separately by ten pipe diameters, can be 10 dB at a frequency of 120 kHz but only 1 dB at a frequency of 20 kHz .

Therefore, an analysis must attach more importance to the difference observed at higher frequencies.

 The following three differential methods start with the most general and then go on to those that are more complex and specific.

(1) The Signature Comparison Method
Each plan has the option to display the difference between two signatures in the PANEL
ANALYSIS. So far, these signatures were recorded on separate sheets of paper to allow visual analysis by the user, the difference between the signatures being neither calculated nor displayed. Some simple plans have an automatic addition of difference displays; in the case of only a few valves, the plans record information indicating which signatures should be used. In addition, the DIF button can manually display the difference between any pair of signatures already displayed on the ANALYSIS PANEL: difference = Sigl-Sig2.

The user points to the first signature, then to the second signature, then to the DIF button and finally to the location where the difference display is to be made. This method produces an exact difference between the signatures recorded for different valves and / or for different stages.

 Some standard plans are organized to automatically display multiple differential signatures. For example, the simplest is Plan 1. It displays differences between the signatures with the pressure and the background signatures for the valves and for the steps. A user can quickly judge results when entering the ANALYSIS PANEL.

2) Differential signature method with a single sensor
Differential signatures are used when it is not possible to remove pressure from a valve to obtain a background noise comparison signature. This method uses a single sensor and three separate signatures to compare a valve with the background noise on either side of that valve. It assumes that the signatures are stable during the collection time. The three signatures are recorded in sequence, on the valve, upstream of the valve, and downstream of the valve. Locations for upstream and downstream signatures may be on another valve or pipe. Although greater site separation is desirable, valid comparisons can be made using sites on the pipe near the valve.

This set of three signatures is marked by an Xd sign in a plane that causes the display of three additional buttons above the plane. After collecting signatures, the user activates the button
ANALYZE while the cursor remains on the Xd sign. A
Dedicated ANALYSIS PANEL will appear and display the three signatures on the first line and the two differential signatures (the signature of the valve minus the upstream signature and the signature of the valve minus the downstream signature) on the middle line. The system then automatically produces a recommended result indicating whether or not there is a leak by performing one of the analysis procedures described above.

(3) Differential signature method with two sensors
In some cases where the state of the valve can not be changed and the background noise conditions are unstable, the signatures must be taken simultaneously on the valve, upstream of the valve, and downstream of the valve. This method eliminates erroneous readings due to changes in conditions between signatures. Three sensors would be difficult to manage, but only two sensors are required simultaneously to produce valid differential signatures.

When the cursor is on an Xd sign on the PANEL
OF SIGNATURES, the user activates the MODE button to switch to a two-channel collection. Two buttons will appear instead of three above the plane, the button with the V-Amont being highlighted. The user places the A channel sensor at the valve location and the B channel sensor at the upstream location and presses
EXECUTION. After saving the result, the highlighted button will automatically switch to VD. The user repeats the EXECUTION command with the B-channel sensor at the downstream point of the valve and saves this signature. Reproducibility is complicated in this method due to the fact that two sensors must be well positioned.

The VV button is an option button that can be used to register a differential signature with the two sensors located on the valve. If it is taken, the VV signature is used to apply a channel sensitivity weighting function due to channel "B" in the differential signatures on the display. It is done by automatic calculation as follows: oe (f) = S2vv (f) / S1vv (f) (calculated with both
sensors on the valve)
C2 '(f) = S2 (f) * Cv (f) (applied to channel B upstream
and downstream)
The ANALYSIS PANEL display and automatic analysis are performed in much the same way as for the single-sensor method described above, except that the two valve signatures (V-Amont and V -Aval) appear on the first line, the upstream and downstream signatures appear on the middle line, and the differential signatures appear on the bottom line.

AUTOMATIC PROCEDURES FOR THE ANALYSIS OF SIGNATURES
The automatic analysis by which the invention automates a previously manually executed process will be described now with reference to examples which are given only to illustrate, rather than to limit it. For example, the equations used are examples, and the specific numerical examples can be used to understand the various cases examined.

 The most important question in the proper use of an automatic analysis is the selection of the signatures on which the recommendations will be based. One assumption is that the plan was designed correctly to represent all the valves affecting the contributions of pressure and background noise. Another assumption is that a correct alignment of the valves has been established to produce the conditions of pressurized and pressure-free states necessary for the type of signature.

 The next important question is the amplitude criterion used to quantify the leak. Another optional function is the mathematical frequency weighting function applied to each signature involved in the amplitude criterion calculations.

Usually, the weighting function emphasizes higher frequencies, for example:

<tb> W (f) <SEP> = <SEP> / 2 <SEP> * <SEP> f <SEP> / <SEP> Range
<tb> where the middle of the beach is equal to unity.

 This is due to the reduction of the sensitivity of the sensor with the increase of the frequency and the increase of the acoustic attenuation with the increase of the frequency, without counting the background noise.

A semi-automatic method chosen by the user and described below adds a limit of choice of the band to the weighting, for example:
W (f) = 0 below ft - 0.05 * Beach and above
fb + 0.05 * Beach
In the two signature analysis chosen by the user, each time the user uses the button
DIF in the ANALYSIS PANEL, a ratio R is calculated of the two selected signatures. The analysis of total band differential signature inputs (r, ASP + ax and the result, ASA being the acoustic signature amplitude which is the sum of the attenuation and the relative amplitude) is displayed in FIG. right angle of the differential display. This display is automated. Previous processes required the user to record the attenuation and calculate the ASA. The BAND button and any peak on the differential display can be enabled to replace the analysis with band analysis limited to the dominant frequency chosen.

 The main advantage of organizing valves according to standard plans is that standardized analysis methods can be applied to systems. As the methods have been proven, they can be added to specific plans by the software. They can include any number of different comparisons, as described above. The ratio calculation method can be chosen individually for each comparison, and the frequency weighting function can be used, or not used for each comparison. Thus, the dependence of the results for each article is chosen as maximum / minimum of one or more comparisons, the limit criteria being modified if necessary.

 This analysis technique preprogrammed in the plane can be replaced in the ANALYSIS panel by using the BAND button triggering a calculation of the ratio to the dominant frequency.

The differential signature input analysis is a specific example of the above, and uses the criteria of a point-to-point relationship (as explained above) to calculate R for both Gate-to-Gate and
Valve Aval. The lower of the two ratios and ASA> x valve are then used to establish the absolute result.

 When a group of parallel valves in identical states can not be manipulated, a direct comparison analysis can be done to calculate the relative flow rates of the leaks in the group. The most dominant frequency is chosen for the group. The ratio of the amplitude of each signature to the sum of all the amplitudes of the signatures, chosen at the dominant frequency, is the proportional flow of leakage.

 Three kinds of reporting criteria will be explained now. The signatures to be used can be selected by the user or automatically, as needed. For example, if adjacent signatures in a row or column are valve signatures and background signatures, they can be chosen automatically.

For a ratio criterion at a frequency f chosen by the user, the ratio is calculated as follows:
R = Sl (f) / S2 (f)
The dominant frequency is automatically selected at the highest amplitude of a frequency-weighted signature. If the highest peak is found at the lowest frequency, the next highest peak is selected. Any other frequency can be manually selected by activating the BAND button; however, this is again automatically maximized in 8% of the frequency concerned. At the selected frequency, the ratio is
R = Sl (f) / S2 (f)
For the ratio RMS (RMS), the RMS ratio is calculated as follows:

For point-by-point report criteria, the ratio RMS is calculated as follows:
C (f) = (Sl (f) -S2 (f (sl (f) S2 (f)}
R = E (C (f) * A (f)) / A (f)

or
R is the ratio of weighted differential signatures (-1 <R <1);
V is the variance of the weighted signatures
Sl (f) is the function of the amplitude, and
is a sum of 10% to 100% of the frequency range for each f where Sl (f) or S2 (f)> 12 dB ASA; and
A (f) is a second weighting function to exclude amplitudes at lower frequencies and take into account the acoustic attenuation (which is a function of frequency and distance) of a linear system: A (f) = 1 (S1 (f) + S2 (f)) + (Slmax + S2max)> 0.1,
= 10 * (Si (f) + S2 (f)) / (Slmax + S2max) in other cases.

 This approach avoids the weighting function W (f).

The report, once calculated, can be used to determine the existence and significance of a leak so:
Large leak: R> 25dB
Average leakage: 25dB> R2 lOdB
Small leak: lOdB> R 2 OdB
Waterproof: R <OdB
The absolute result specification uses R and V therefore:
Waterproof: R <O and V <0,2
Leakage: R> 0.3 and V <0.2
Otherwise, a judgment of the user is necessary.

If a leak is found, the importance of the leak is automatically given from the maximum ASA of the smoothed valve signature:
Large: ASAmax 2 55dB Medium: 55dB> max r 35dB
Small: ASAma <35dB
For steam traps, time analysis is required. The system takes a temporal scan signature of the average amplitude over a 10% bandwidth centered on a chosen frequency. The frequency can be chosen when the user activates the BW button.

A standard spectrum of frequencies appears automatically.

The user points to a peak of the signature, and this frequency is chosen. When the user activates the EXECUTE button, a time signature records an average amplitude for 30 seconds, 60 seconds, or 120 seconds (controlled by the MOY button on the CONTROL PANEL).

 The automatic analysis first identifies the open and closed states on the time signature with pressure. The maximum amplitude (P <aX) is calculated as the average of the 5% highest points and the minimum amplitude (Amin) is the average of the 10% lowest points. If the ratio Amax / A <ax / I, is less than 5 dB, we speak of a state closed by an obstruction. If a background noise signature (without pressure, time or frequency signature) is obtained on the trap, it can be further classified. The average amplitude of signatures with pressure (Pav) and background noise (Bav) and the ratio Pav / Bav are calculated. If the ratio is greater than 20 dB, we are talking about an open state. If the ratio is less than 5 dB, we speak of a closed state by plug.

If the trap is not blocked, any point of the amplitude above (Ar.ax + Ar-n) / 2 is called open, and any point below (Na + Aun) / 2 is called closed . The result is classified as follows:
Bad: A <, / B> 3 dB
or: Duration of all open periods
> 5 seconds
or: The time between the beginning of the periods
open> 15 seconds
Satisfactory: In other cases.

 Whenever the ANALYTICAL PANEL calculates a recommended result, it is automatically displayed in the CONCLUSION PANEL and marked as such (flashing). When the user points to a recommended result in the CONSOLIDATION PANEL, it becomes an accepted result that can be changed by pointing to it again. If they are not accepted before returning to the CONTROL PANEL, all recommended results are lost.

 The operation of the CONCLUSION PANEL will be explained with reference to Figure 34. For the most part, automatically recommended results are displayed, which results may be accepted or rejected by the user when formulating his conclusion. When this panel is called (step 3402), the result table is displayed (step 3404) with the article, the result, the importance, and a comment for each article being displayed under the basic article. The user can enter a conclusion as to whether a leak is found to exist (steps 3406 to 3410), his estimate of the size of the leak (steps 3412 to 3418), and a comment (steps 3420 to 3424). user can also fill any item below the cursor that has no result, with a copy of the line where the cursor is placed (steps 3426 and 3428) or he can activate ESC and return to the CONTROL PANEL (steps 3430 and 3432 ).

 A useful feature of this invention is the use of multiple levels of instructions for the user. The collection of leak signatures requires a complex procedure for collecting as much information as possible. It is only after having gained a lot of experience that a user will recognize unnecessary steps in certain circumstances. The determination of pressures usually imposes maximum test speeds. Therefore, the system has two levels of instructions that can be selected by the user. Several instructions are displayed at either level and others only at the beginner level. They help to go faster and minimize the training needed.

The system remains at the previous instruction level until the user resets it by the following method. The user leaves the PANEL OF
COMMAND to go into the DOS and it reboots the system by an appropriate command as follows:
AVLA / b Beginner level (full instructions)
AVLA / e Expert level
The first type of instruction contains the status messages displayed on the left above the connection diagram. Most of these show both levels. The instructions for collecting signatures follow the following order:
Place the sensor on item 5.1 and press EXECUTION
Verification: replace the sensor on the 5.1 valve and
press EXECUTION
Good reproducibility, press SAVE
Plan completed
Other messages are:
Not Ready Replace Again
Not a signature step
No data acquired
The beginner level adds some other messages:
The alignment of step 1 is not complete
The second type of instructions uses the panel
YES / NO to ask a question and to receive an answer. Although this type is widely used with panels to prevent errors and data loss, this description describes in detail mainly its use in the collection of signatures at the beginner level. The valves are grouped under a fundamental article with a plan of control. A plan will provide a signature entry for each valve pressure combination (open / closed) necessary to address any potential source of leakage.

A beginner needs to follow a fixed procedure of opening / closing a valve and collecting signatures. In fact, the most important reason is to respect plant safety and prevent open fluid paths. The system contributes by guiding the user through every detail of the valve alignment informing about the valve that is open / closed and the signature to be collected at each step, in addition to the messages described above. for collection of signatures.Before starting and after completion of each step in the plan, a sequence of questions appears in the YES / NO panel as in the following example:
Close Article 5.1- READY?
Open Article 5.0- READY?
Open Article 5.2- READY?
It should be noted that a proper design of the plane (without replacing the automatic PANEL input) places the valve closures in a step devoid of signatures preceding a valve opening step, which automates valve alignment. and the entry of signatures. The system will automatically move the cursor from the plane and request the opening / closing of the valves and require the collection of necessary signatures. The progression through the plane v first from top to bottom, then from left to right. If the user forgets a signature, the system tries to return to it before advancing to the next step. If the user tries to go to a different step with the arrow buttons, a sign
YES / NO request confirmation:
This step is not completed. Are you sure?
The system notifies the user when performing actions that are not in the prescribed sequence, and then prompts the user to perform all the necessary actions. So even if the user changes the order, all necessary actions will be executed; otherwise some of them could be skipped.

 A feature related to this and of particular value for beginners, is the HELP function. If the user does not know how to use a particular button, they can keep it on for at least one second and receive a context-related help message. If it turns the button on and off in less than one second, this button will perform its normal function. Of course, other commands can be used, such as using the right mouse button to call the HELP message and a left button to trigger normal operation. Alternatively, a HELP button similar to the F1 key used in many standard applications may be provided. An indication of the battery voltage and brightness and contrast control of the display may be included in the HELP message.

 Finally, the operation of the digital signal processing executed in the FFT module 106 will be further described, with reference to FIGS. 35 to 37.

 When the FFT module is initialized, the following data is confirmed by default (step 3502): analysis = FFT, gain = mid-scale, frequency range = 200 kHz, frequency band = 92 kHz. Then, a user's order is expected (step 3504).

 At this point, the user can reset the scan mode (steps 3506 to 3510) or the sampling rate (steps 3512 to 3516) or give a wake up command (step 3518). In the latter case, U is sent (step 3520), and the FFT module samples and processes analog data (step 3522 explained below with reference to Fig. 36) and waits for a new command (step 3524). Then, the user can adjust the band (steps 3526 to 3530), sum to the band (steps 3532 to 3536), cause the processed data to be sent from channel A or channel B (steps 3538 and 3540), set the filter and channel (steps 3546 to 3550), or put the module in the idle mode.

 The step of sampling and processing the analog data will be explained with reference to FIG. 36. When this step is called (step 3602), the module according to the number of activated channels (step 3604), samples either 16,384 points on a single channel (step 3608), or 8,192 points on two channels (step 3606). Then, in accordance with the selected process, (step 3610), the module executes an FFT (steps 3612 to 3620), an autocorrelation (step 3624), or an envelope computation (steps 3626 to 3632). If the amplitude peak is above or below the range, the gain may be increased or decreased automatically (steps 3634 to 3642), and the apparatus returns to the initial process (step 3644). Previous processes required manual judgment and the recording of appropriate gain.

 The step of sending processed data, as in steps 3540 and 3544 of operation of the FFT 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 amplitude of the signal is in the range (step 3706). If this is the case, each pair of amplitude points is averaged, and data from 10% to 100% of the frequency range is sent (step 3712). Otherwise, it is determined whether the signal amplitude is below the maximum gain range (step 3708) or above the minimum gain range (step 3710). If either of these conditions is met, step 3712 is executed.

Otherwise, step 3712 is not executed. The apparatus returns to the initial process (step 3714).

 The foregoing description is for explanatory purposes rather than limiting. Those skilled in the art will understand that other embodiments are possible within the scope of the invention. For example, the device may be equipped with a barcode reader for use in factories having valves bearing these codes. You can also use a color screen to allow a superposition of signatures.

 Instead of Fast Fourier Transform conversion, several other types of mathematical conversion may be used, such as time domain, correlation, convolution, or time band limited correlation. Instead of software, a firmware or the like can be used to guide the user and execute the analysis. The specialists having read the present description will easily understand how to make appropriate modifications for this purpose, without departing from the scope of the invention.

Claims (63)

 Apparatus for performing a process for testing a valve system against leakage, said apparatus characterized by comprising:  sensor means for receiving acoustic signals from the valve system and for converting these acoustic signals into electrical signals;  means for receiving the electrical signals and subjecting them to a transform calculation, for producing at least two acoustic signatures, and for generating digital output data representing said acoustic signatures; and  calculating means for (i) receiving said digital data and for comparing said acoustic signatures to obtain a result of the comparison and for (ii) from this result automatically generating a recommended result regarding the existence of leaks in the valves.  2. Apparatus according to claim 1, characterized in that the result of the comparison is an amplitude ratio of said at least two acoustic signatures at a selected frequency taken from a group comprising a manually selected frequency and an automatically selected frequency.  Apparatus according to claim 1, characterized in that the result of the comparison is the ratio of the weighted weight squared means of said at least two acoustic signatures, the squared averages being calculated over a predetermined frequency range.  4. Apparatus according to claim 1, characterized in that the result of the comparison is a root mean square, calculated over a predetermined frequency range, weighted amplitude ratios, said at least two acoustic signatures.  5. Apparatus according to claim 1, characterized in that the amplitudes of the acoustic signatures at a dominant frequency are summed to generate a sum; and in that the result of the comparison for each valve is a ratio between said sum and the amplitude of the acoustic signature of this valve at the dominant frequency.  6. Apparatus according to claim 1, characterized in that it further comprises means for storing the digital data representing the acoustic signatures and a conclusion derived from the recommended result and said at least two acoustic signatures.  7. Apparatus according to claim 1, characterized in that it further comprises display means for displaying said at least two acoustic signatures and said recommended result.  8. Apparatus according to claim 1, characterized in that the display means also displays a difference calculated from said at least two acoustic signatures.  9. Apparatus according to claim 1, characterized in that the computing means comprise interface means for receiving the orders of a user concerning the organization, control, analysis and / or report relating to a statement of leaks from the valves.  10. Apparatus according to claim 9, characterized in that the interface means comprise a touch screen.  11. Apparatus according to claim 1, characterized in that it also comprises connection means for sending said digital data representing the acoustic signatures and the conclusion to an external computer.  Apparatus according to claim 11, characterized in that the connection means comprises a port for a flexible floppy disk drive.  Apparatus according to claim 1, characterized in that it also comprises digital storage means for storing a digital database and a group of test structures for said test process.  14. Apparatus according to claim 9, characterized in that said calculating means comprise control and display means for guiding the user in understanding said test process.  Apparatus according to claim 14, characterized in that said calculating means comprises selection means for controlling the interface means to allow the user to make the required choices for said test process.  16. Apparatus according to claim 15, characterized in that said selection means allow the user to choose a parameter and control the sensor means and the conversion means so that the acoustic signatures are produced in agreement with the chosen parameter by the user.  Apparatus according to claim 16, characterized in that the parameter is the frequency range.  Apparatus according to claim 16, characterized in that the parameter is the frequency bandwidth.  Apparatus according to claim 16, characterized in that the parameter is the type of conversion.  20. Apparatus according to claim 1, characterized in that the parameter is a method of averaging.  Apparatus according to claim 15, characterized in that said selection means also controls the apparatus for collecting the acoustic signatures in accordance with the choices made by the user.  22. Apparatus according to claim 15, characterized in that, when the interface means simultaneously display one or more acoustic signatures, and the user uses the interface means to indicate a portion of one of said acoustic signatures, the The interface means generates a touch signal and sends the signal to the control means which then changes a scale parameter by which one or more of the acoustic signatures are displayed on the interface means in accordance with the touch signal.  23. Apparatus according to claim 15, characterized in that the interface means have several ways for the user to operate, and in that the interface means comprise assisting means for displaying, when the user performs one of the predetermined ways of putting into action, a context-sensitive descriptive message.  24. Apparatus according to claim 14, characterized in that it also comprises digital storage means for storing several instructions relating to the operation of the calculation means.  25. Apparatus according to claim 24, characterized in that the conversion means comprise storage means for storing several instructions relating to the operation of said conversion means.  26. A method for testing a valve system with respect to leaks in the valves, characterized in that it consists of:  (a) positioning at least one sensor on the valve system to receive two different acoustic signature signals from a valve in the valve system and to convert the acoustic signals into electrical signals;  (b) converting the electrical signals to produce acoustic signatures and forming a digital data output signal representing the acoustic signatures;  (c) comparing at least two of said acoustic signatures on the basis of said digital data to obtain a comparison result; and  (d) generating a recommended result regarding valve integrity from the result of the comparison, and displaying the recommended result for a user.  27. The method of claim 26, characterized in that the result of the comparison is a ratio of the amplitudes of said at least two acoustic signatures at a selected frequency which is taken from the group comprising a manually selected frequency and a frequency automatically chosen.  28. A method according to claim 26, characterized in that the result of the comparison is a ratio of squared means of the weighted amplitudes of said at least two acoustic signatures, the squared averages being calculated over a predetermined frequency range.  29. A method according to claim 26, characterized in that the result of the comparison is a root mean square over a predetermined frequency range, weighted ratios of the amplitudes of said at least two acoustic signatures.  30. The method according to claim 26, characterized in that the amplitudes of the acoustic signatures at a dominant frequency are summed to generate a sum; and in that the result of the comparison for each valve is a ratio between said sum and an amplitude of the acoustic signature of this valve at the dominant frequency.  31. The method of claim 26, characterized in that it further comprises storing said digital data representing the acoustic signatures and a conclusion derived from the acoustic signatures and the recommended result on a digital storage medium.  32. The method of claim 26, further comprising (e) sending said digital data representing acoustic signatures and concluding as an output signal to an external computer.  33. The method according to claim 26, characterized in that step (e) comprises writing said digital data representing the acoustic signatures and the conclusion, on a medium that can be read by a machine.  34. A method according to claim 26, characterized in that it also comprises a step of supplying an information database and a set of plans constituting standard test structures or modifications of test structures. derived from standard test structures, said plans also including structures for automated analysis.  The method of claim 34, characterized in that step (e) comprises i) compressing said digital data representing the information database, the plans, the acoustic signatures, and the conclusion, into a file. compressed, and (ii) write the compressed file on a medium that can be read by a machine.  36. Process according to claim 34, characterized in that the valves of the valve system are grouped into articles and receive an article number, each article number being identified by a fundamental number (group number) and a sub-number. -number, a basic article having a specific function for the system and all other articles having functions related to the fundamental article.  37. A method according to claim 36, characterized in that each group of articles grouped under a fundamental article is assigned to one of said planes.  38. The method of claim 37, characterized in that all items are compiled into an ordered database with categories of information that include items, plans, and identification information.  39. A method according to claim 38, characterized in that it consists of several searches in the database ordered according to any of the categories of information, to select a test sequence of a group and to separate the search results by the state of completion of the test.  40. A method according to claim 34, characterized in that it further comprises a display step for the user of instructions guiding the user in the understanding and conduct of the test method.  41. A method according to claim 40, characterized in that it also comprises a step to allow the user to make the choices required for the test method.  42. A method according to claim 41, characterized in that the step of allowing the user to make his choices consists in allowing the user to choose a parameter, the acoustic signatures being produced in accordance with the parameter chosen by the user. 'user.  43. The method of claim 42, characterized in that the parameter is the frequency range.  44. The method of claim 42, characterized in that the parameter is the frequency bandwidth.  45. The method of claim 42, characterized in that the parameter is the type of conversion.  46. The method of claim 42, characterized in that the parameter is a method of calculating the average.  47. A method according to claim 41, characterized in that the acoustic signatures are collected in accordance with the choices made by the user.  A method according to claim 41, characterized in that, when one or more acoustic signatures are simultaneously displayed for the user and the user indicates a portion of said acoustic signatures, a scale parameter, by which one or more of these acoustic signatures are displayed, is changed.  49. The method of claim 41, further comprising a step that when the user makes one of the choices in a predetermined manner, displays a context-sensitive descriptive message.  50. The method of claim 40, characterized in that the step of displaying the instructions consists of:  (i) prompt the user to configure the valve system appropriately;  (ii) in the case of a positive response from the user, perform the test method; and  (iii) in the case of a negative response from the user, display a warning message to ensure the safety of the user and prevent the collection of invalid acoustic signatures.  51. The method of claim 50, further comprising inviting the user to perform a selected operation in the group that includes the operations of  (i) placing the sensors on a portion of the valve system to test the system;  (ii) remove and replace the sensors;  (iii) storing an acoustic signature, when the acoustic signature proves to be good; and  (iv) correct a situation that causes the production of a bad acoustic signature.  52. A method according to claim 40, characterized in that it also consists in choosing among two or three contiguous signatures the one which is the highest and in marking the highest signature with a result of a difference reproducibility test of the quadratic averages (RMS)  53. Process according to claim 40, characterized in that it also consists of  (i) prompting the user to remove and return the sensors and to repeat the collection of signatures; and  (ii) calculate the reproducibility by the difference between the root mean square (RMS) to verify the correct coupling of the sensor.  54. The method of claim 40, further comprising inviting the user to complete the test and the analysis of the group of articles in a correct sequence.  55. The method of claim 54, further comprising allowing the user to advance to a place in the plane he has chosen by maintaining the complete instructions to complete the test.  56. The method of claim 40, characterized in that step (c) comprises:  (i) displaying two or more signatures;  (ii) receiving a user input representing a selection of a first signature and a second one of said two or more displayed signatures and a location;  (iii) determining the difference between the first signature and the second signature at the location chosen by the user; and  (iv) displaying the difference obtained in step (c) (iii)  The method of claim 56, characterized in that step (c) further comprises determining the recommended result based on the difference, and displaying the recommended result.  58. The method of claim 57, further comprising temporarily storing one or more recommended results until the user accepts them or enters different conclusions from the recommended results.  59. A method according to claim 58, characterized in that step (c) (i) comprises the automatic selection of signature pairs for display, comparison and recommendation of the result.  60. The method according to claim 26, characterized in that step (d) comprises the correction of acoustic signatures for acoustic attenuation which consists of an attenuation as a function of frequency and distance.  61. Process according to claim 26, characterized in that  step (a) is to automatically prompt 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 according to the instructions (iii) attaching the sensors to the predetermined locations on the valve system, and (iv) indicating that the sensors have been attached at the predetermined locations, the acoustic signals not being received until the user has indicated in step (a) that the predetermined valves have been opened or closed according to the instructions and that the sensors have been attached at the predetermined locations,  the user being prompted automatically to perform steps (a) and (b) several times for several open or closed valve configurations in accordance with a sequence stored in the automated interface apparatus  step (b) is to convert the electrical signals by the Fast Fourier Transform (FFT) method to produce the acoustic signatures, and to display the acoustic signatures for the user; and  step (c) is to automatically calculate a ratio of said at least two signatures and to automatically determine in accordance with a stored rule, the result of the comparison according to the ratio; and  step (c) further comprises prompting the user to enter the conclusion based on the acoustic signatures displayed in step (c) and the recommended result.  62. The method of claim 61, wherein step (c) comprises receiving a user's order, indicating which of the acoustic signatures are to be compared, and generating the ratio of the acoustic signatures selected by the user. .  The method of claim 26, characterized in that step (a) comprises positioning the sensor at one or more locations on the valve system, and controlling the valve system to provide a plurality of different differential pressures in the system. of valves.