EP3701152A1

EP3701152A1 - Method and device for maintaining a pumping system in operational condition

Info

Publication number: EP3701152A1
Application number: EP18789158.5A
Authority: EP
Inventors: Patrick PHILIPP; Maurice MARTAUD; Pierre GRAMONT
Original assignee: Suez Groupe SAS
Current assignee: Suez International SAS
Priority date: 2017-10-25
Filing date: 2018-10-23
Publication date: 2020-09-02
Also published as: US11920600B2; MA50444A; CL2020001085A1; WO2019081524A1; AU2018356378A1; FR3072737A1; CN111247344B; FR3072737B1; US20200340483A1; CN111247344A

Abstract

A method for maintaining a pumping system (2), that is part of a pumping station (1), in operational service (30), said pumping system (2) comprising a pump (20), a motor (21) driving the pump (20), and a pipe for discharging fluid by the pump (20). Said method comprises at least the following steps: - measurement of physical values, operational characteristics of the pumping system (2), including hydraulic values that are characteristic of the state of the pump discharge pipe (20); - analysis and interpretation of the measured physical values with the aim of detecting one or more anomalies; - pre-diagnosis of the probable causes of the detected anomalies and determination of the preventive and curative actions to take on the pumping system (2); automatic implementation of the preventive and curative actions on the pumping system (2).

Description

Method and device for maintaining in operational condition a pumping system

Technical area

The invention is in the field of pumping, such as urban hydraulic pumping which comes into play in the collection and transport of waste water and in the distribution of water. The invention more generally relates to the management problems of water pumping stations comprising one or more pumping systems.

State of the art - Description of the technical problem

In the field of the management of pumping stations there are several types of actors each offering a particular management service.

The first type of actors are the pump manufacturers. They benefit from a detailed knowledge of the operation of their product and can thus finely detect operating drifts that can lead to pump failures. However, the management systems proposed by the pump manufacturers are not, or are not, adapted to pumps from other manufacturers, or to the pumping station as a whole, when it includes several pumps. origin and different invoice for which it is necessary to monitor several different parameters such as hydraulic or electrical parameters.

A third type of actors are the component manufacturers used in pumps and their engines. These components include bearings, fittings, etc. Again, this type of player is very specialized in its technical field and even if the systems it offers will very well detect a failure of the component, failures due to other components will not be detected.

A fourth type of actors are service providers who will design generic tools for managing pumping stations. These The tools take into account all the components of the pumps and motors, but they must be parameterized correctly by an operator specialized in programming and having a good knowledge of the systems that make up the pumping station. The parameterization of such tools requires knowledge that electromechanical operators specialized in the management of pumping stations do not possess. In the same way, the operators specialized in the parameterization of the management tools do not have a very detailed knowledge of the operation of each equipment of the pumping station.

An object of the invention is notably to propose an automatic analysis tool for monitoring and analyzing the operation of the pumping station. This analysis tool also makes it possible to detect mechanical failures of the machines making up the pumping station, in particular pumps and motors. The analysis tool proposes a causal evaluation as well as preventive and curative actions to carry out following a detection of one or more failures on the various components of the pumping station. If the actions do not require the intervention of an operator, the tool can transmit the appropriate instructions to the pumping station.

Summary of the invention

The present invention provides for this purpose a method of maintaining in operational condition a pumping system forming part of a pumping station. The pumping system comprises in particular a pump, a motor driving the pump, a pipe for delivery of fluid by the pump, a pipe for suction of fluid by the pump. The method comprises at least the following steps:

measurement of physical quantities characteristic of the operation of the pumping system, including physical quantities characteristic of the state of the discharge pipe of the pump, of the state of the suction pipe of the pump;

- analysis and interpretation of physical quantities measured to detect one or more anomalies; - pre-diagnosis of the probable causes of the anomalies detected and determination of the preventive and curative actions to carry out on the pumping system;

- automatic implementation of preventive and curative actions on the pumping system.

The method may furthermore comprise a step of analyzing and interpreting the operating curves of the suction and discharge lines of the pump and a step of monitoring the sub-emergence of a water intake at the inlet of the pump. pumping system.

The method notably comprises a step of analyzing and interpreting the revolution of operating points of the pump and a step of analyzing and interpreting the evolution of operating points of the engine.

The method may also include a step of controlling the energy performance of the pumping system.

The method may also include a step of detecting a cavitation phenomenon.

The submergence control stage of the water intake may notably take into account a water level in the water intake, a flow rate sucked by the pump at the intake, physical description parameters. of the water intake.

The step of analysis and interpretation of the operation of the discharge pipe can take into account the evolution over time of the following parameters: a pressure at the delivery of the pump, a flow served by the pump, a current intensity called by the engine, an active power called by the engine.

The step of analyzing and interpreting the operation of the suction pipe takes into account the evolution over time of the following parameters: a suction pressure of the pump, a flow rate served by the pump, a current intensity called by the engine, an active power called by the engine, a total head, a NPSH available.

The invention further relates to a device for maintaining in operational condition a pumping system forming part of a station of pumping. Said pumping system comprises in particular a pump, a motor driving the pump and at least one discharge pipe and a pipe for suction of fluid by the pump, said device being characterized in that it comprises:

hydraulic and mechanical sensors making measurements of hydraulic and mechanical quantities on the pump, the discharge pipe, the suction pipe;

- Electrical and mechanical sensors performing measurements of electrical and mechanical quantities on the engine;

an electrical cabinet for the pumping system collecting the measurements of the hydraulic, electrical and mechanical sensors, transmitting operating instructions to said pumping system;

a supervision system comprising a computer on which a central program executing the method for maintaining a pump system in operational condition, said supervision system being able to automatically transmit commands to the electrical cabinet in according to the results of analysis, interpretation and pre-diagnosis, said monitoring system comprising a man-machine interface for displaying the results of analysis, interpretation and pre-diagnosis.

Advantageously, the invention makes it possible to implement automatically the appropriate actions to prevent or solve operating problems of the pumping station. Description of figures

Other advantages and features of the invention will appear on examining the detailed description of several non-limiting embodiments, and the appended drawings, in which:

FIG. 1 represents a simplified version of a pumping station according to the invention;

FIG. 2 represents an example of a pumping system;

FIG. 3 represents various possible steps of the method for maintaining in operational condition a pumping system according to the invention;

FIG. 4 represents operating curves of a pump of a pumping system;

FIG. 5 represents an analysis diagram of the operation of a pump according to the invention;

FIG. 6 represents operating curves of an engine of a pumping system;

- Figure 7 shows load curves of the motor. These embodiments being in no way limiting, it will be possible to consider variants of the invention comprising only a selection of characteristics described or illustrated subsequently, isolated from the other characteristics described or illustrated (even if this selection is isolated at within a sentence including these other features), if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the state of the art. This selection comprises at least one preferably functional feature without structural details and, alternatively or with only a part of the structural details, if this part alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the invention. prior art. detailed description

FIG. 1 shows an example of a pumping station 1 comprising one or more pumping systems 2. The pumping system 2 comprises a pump, a motor, a water intake and an outlet pipe of the pump. The pumping system 2 may further comprise an inlet pipe connecting the pump to the water intake when the pump is not immersed at least partly in the fluid that it must pump. The pumping system 2 further comprises sensors measuring parameters characteristic of the operation of each component of the pumping system 2. Each pumping system 2 is connected to an electrical cabinet 3 intended for the management of the pumping system 2. The cabinet The function of the electrical control unit 3 is to control and control the pumping system 2. The electrical cabinet 3 is part of the pumping station 1. The electrical cabinet 3 receives the various measurements, or inputs 4, made by the sensors of the system 2 and in particular transmits to the pumping system 2 commands or outputs 5. The electrical cabinet 3 comprises at least one processor on which runs a local program 6 for managing the operation of the pumping system 2. The inputs 4 are The electrical cabinet 3 then transmits the inputs 4 for processing to a supervision system 7. The supervision system 7 p control and control one or more pumping stations. In order to simplify the presentation, in the following we will speak only of a pumping station. The supervision system 7 is a remote server comprising at least one processor or computer that performs analysis processing on the inputs 4 via a computer program or central program 8. The central program 8 performs an analysis data and measurements from several pumping systems 2 to perform a monitoring function of the pumping station 1 as a whole. The supervision system 7 furthermore comprises a database aggregating all the physical characteristics of the pumping systems 2 and all their components. The supervisory system 7 is adapted to transmit instructions and commands to each pumping system 2 through each electrical cabinet 3. The electrical cabinet 3 adapts the instructions to the equipment to which these instructions are addressed in order to translate them into a signal interpretable by the equipment. The equipment may for example be the pump, the motor or a valve. To this end, the electrical cabinet 3 can be configurable including via an API or PLC Programmable Industrial. The configuration of the electrical cabinet 3 makes it possible to adapt this cabinet to different pumping systems 2, comprising, for example, equipment from different manufacturers. The electrical storage unit 3 can advantageously be programmed by an electromechanical operator who can enter thresholds and parameters to be taken into account to carry out the monitoring and supervision of each pumping system 2 of the pumping station 1. Said thresholds and parameters can be adapted to each device. The thresholds and parameters can be transmitted to the supervision system 7 and stored in the database. The central program 8 uses the characteristics of the pumping station 1, the measurements made in real time and the parameters and thresholds entered by the operator in order to perform the monitoring function. The monitoring function performs an analysis of all of this information in order to detect any drift, related to an anomaly that could lead to a failure or malfunction of the pumping station 1. On detection of a drift, the system of Supervision 7 analyzes all the data in order to determine the cause of said drift according to rules defined according to the practices of the pumping station management domain 1 as well as according to expert feedback from analysts of the causes of failure of the pumping stations. pumping systems. These rules are also stored in the database. From the analyzes carried out, rules and anomalies detected, the central program 8 can determine one or more preventive or curative actions to be carried out. These actions can be automatically transmitted to the electronic control unit 3 in the form of commands and transmitted to a human machine interface for consultation by an operator. The operator can decide whether to perform these actions or other operations. The operator can also, via the man-machine interface, to enter commands to be implemented by the pumping station 1. The commands that can be implemented are, for example, stopping the pump and the motor, opening or closing a valve pumping station, engine speed change instructions, etc.

FIG. 2 represents an example of a pumping system 2. The pumping system 2 comprises at least one pump 20, a motor 21, a coupling device 22 of the motor 21 with the pump 20.

The pump 20 is for example a dynamic pump which can be of the volumetric or rotodynamic type.

The motor may be an asynchronous type electric motor or synchronous type permanent magnet or variable reluctance.

The pump 20 comprises a fluid inlet 23 via a suction or intake pipe and a fluid outlet 24 via a discharge pipe. The inlet 23 is thus connected to a suction pipe, itself connected to a water intake either via a strainer 25 or directly without a strainer. The suction of water can for example be done in a reservoir 26. The outlet 24, connected to a discharge line, feeds a system, not shown, of water transfer. The water transfer system may comprise a pipe or network of pipes of different diameters and lengths.

Alternatively, in an example not shown, the pump can be dipped directly into the liquid. In this case, the pumping system does not include a suction pipe.

FIG. 3 represents several steps of the method 30 according to the invention for maintaining the pumping system 2 in operational condition. The method 30 according to the invention notably comprises various steps of operation analysis and pre-diagnosis of anomaly in the The described example is for a single pumping system, it can be reproduced in the same way for a pumping station 1 comprising more than one pumping system 2. The method according to the invention performs several functions:

- a monitoring function (monitoring) of the pumping station 1;

an anomaly detection function;

a function for analyzing detected anomalies;

- a function of pre-diagnosis of the anomalies making it possible to determine the probable causes of the anomalies;

- and, according to the causes identified, a function of proposal of actions to be carried out, an automatic generation of commands to be applied by the equipment of the pumping system 2.

A first step 31 of the method according to the invention is a step of updating the data and technical information on the pumping station as well as on the water transfer system that it serves, in the database of the system. supervision 7. This information is for example the description of the pumping station 1 with all of its elements. In particular it is important to inform the characteristics of the invisible parts of the pumping station 1, including their dimensions. Among the information describing the pumping station 1, it is also necessary to have plans and dimensions to locate the equipment of the pumping station 1 relative to each other and in particular the pump relative to other equipment and the pump by compared to measuring instruments, especially hydraulic ones.

The information relating to the system served by the pumping station 1 are physical characteristics of said system served as well as the various elements composing it. For example, the system served by the pumping station, or water transfer system, may include one or more pipes of different diameter and length. The information also includes a description of the control modes of the pumping station 1, defined to satisfy the needs of the system served by the pumping station 1. Among the information, you can also find the different operating states of the pumping station: normal operating modes, exceptional operating modes, degraded or crisis, as well as the control modes of the pumping station 1 related to each of the modes of operation of the system.

The information on the pumping station 1 makes it possible to construct a characteristic operating curve of the pumping station 1 which represents an evolution of the water flow at the outlet of the pumping station 1, as a function of the total head.

A second step 32 of the method according to the invention is a step of updating in the database the information on the equipment of the pumping station 1, in particular on the pump 20, the motor 21 and the delivery pipes and the suction and intake. Equipment information includes performance curves for pumps and motors.

The performance curves of the pump 20 are in particular the following curves:

- the hydraulic performance: total head as a function of the pump flow;

- the hydraulic efficiency of the pump as a function of the flow rate of the pump;

the mechanical power called by the pump on its shaft as a function of flow;

a NPSH (Net Positive Suction Head) required by the pump: that is to say the difference between the liquid pressure and the saturating vapor pressure at each point of the pump;

- the specific energy consumption of the pump.

The performance curves of the engine 21 are in particular the following:

- the active power called according to the mechanical power delivered on the motor shaft;

- the efficiency of the engine; the displacement power factor or cosine phi: the displacement power factor represents the value of the angular phase difference between the voltage and the intensity of the current in the motor at the fundamental frequency (generally 50 or 60 Hz); the current intensity called as a function of the speed of rotation of the motor shaft;

the torque as a function of the speed of rotation of the motor shaft;

the speed of rotation of the engine as a function of the mechanical power delivered on the motor shaft.

The first and second steps 31, 32 may be implemented at the commissioning of the pumping station 1 and then at each modification made on the pumping station 1 or the system it serves, or at each modification of a component of the pumping station 1.

A third step 33 is a step of measuring or calculating physical quantities and in particular hydraulic, to characterize the current operation of the pumping system 2. The third step is performed periodically during operation of the pumping station 1. The measurements made are dated and stored progressively in the database of the supervision system 7 with their date, thus constituting a history. Each hydraulic quantity is associated with an uncertainty and a range of variation of said magnitude.

A first hydraulic quantity is a flow rate of the pump that can be measured directly or calculated from other measurements.

A second hydraulic measured quantity is a geometric height of the system fed by the pumping station 1, with respect to said pumping station 1. This geometric height represents a minimum elevation that the pump must overcome in order to supply the system that it serves. .

A third hydraulic quantity is a total head or HMT. The manometric height can be defined as the sum the geometric height and pressure drops at the suction and discharge of the pump.

A fourth hydraulic quantity is a total dynamic height. The total dynamic height, or HDT, can be defined as the sum of the total head and the dynamic pressure difference between the inlet and outlet of the pump.

Mechanical quantities can also be taken into account as vibration levels. A fourth step 34 is a step of calculating a service point or operating point, characteristic of the operation of the pump at a given instant. The service point is determined from the hydraulic quantities calculated or measured during operation. The service point can be defined at a given time by a flow rate and a total head.

A fifth step 35 is a step of calculating physical quantities including electrical and mechanical.

The measured electrical quantities are the intensity of the current called by the motor 21 and the supply voltage of the motor, as well as the variation range of these two electrical quantities.

The fifth step 35 is also a step of determining the powers: active, reactive, apparent, deforming and their ranges of variation. The uncertainties on the calculations of the different powers are also determined.

The active power, can be defined as the useful power to the supply of the work of the drive machine.

Reactive power is defined as the power required for the operation of the machine, here pump 20.

Apparent power is defined as the power that actually flows through equipment.

Deforming power is a fourth power, present in circuits including electronic components that create non-linear loads and therefore harmonics. The deforming power is the power put into play by the harmonic component.

The fifth step 35 comprises a determination of the various power factors, ie the cosine phi, the total power factor and the total harmonic distortion rate as well as the uncertainties on the various power factors.

The total harmonic distortion rate is also referred to as the distortion power factor.

The fifth step 35 is implemented cyclically during the operation of the pumping system 2. The measurements and the results of the calculations of these electrical quantities are stored in the database with a date and their measurement or calculation uncertainty. as well as their range of variation in order to constitute a history. A sixth step 36 is a step of determining a service point of the motor and its fluctuation range.

The sixth step 36 includes a step of determining an operating range of the motor located in the vicinity of a nominal operating point or service point.

A nominal service point of an engine is the one for which it is built to operate at the time of its design.

The nominal service point rarely coincides with a real service point. The service point of the motor is defined as the point of equilibrium between the drive torque developed by the motor and the resisting torque opposed by the load machine.

The operating range around the service point is defined according to the current and torque measurements and their variation range around the rated service point.

The sixth step 36 includes a step of estimating the efficiency of the motor and its range of variation at the point of service. The estimation of the motor efficiency is carried out on the basis of the measurements of the following physical quantities:

- called active electrical power;

- current intensity called; - motor supply voltage.

The engine efficiency estimate is also made from an estimate of the mechanical power absorbed by the pump on its drive shaft.

A seventh step 37 is a step of creating a history of the service points determined during the operation of the pump. The creation of a history consists of storing the various service points in the database of the supervision system 7 in order to be able to follow their evolution. Figure 4 describes the data necessary to describe a reference situation for the operation of the pump. This reference situation will make it possible to analyze the behavior of the pump by following the displacement of the service point with respect to the reference service point, in the reference situation.

Figure 4 shows examples of performance curves of a pump. The performance curves of the pump are based in particular on the data provided by the pump manufacturer. A reference situation is determined, either from measured and calculated data, or from the data provided by the manufacturer to characterize a nominal operation of the pump.

Figure 4 shows a first pump performance curve 40 in nominal operation. The first curve 40 represents a flow rate of the pump as a function of a total pressure head. On the first curve 40 a first initial service point 41 corresponds to a reference service point. The reference service point 41 is obtained by determining the flow rate of the pump as a function of the total head in a reference configuration of the pumping station 1 and the system it serves.

FIG. 4 also represents a second performance curve 42 representing the mechanical power called by the pump on its wheel shaft as a function of the flow rate of the pump. A second reference service point 43 can be defined as a function of the mechanical reference power at the reference flow rate. A third performance curve 44 can be defined from the efficiency of the pump as a function of the flow rate of the pump. A third reference point 45 may be defined as the efficiency of the pump in the reference flow reference situation.

Thus, it is possible to analyze the operation of the pump during an eighth step 38. The eighth step 38 is a step of comparing the running point of operation of the pump with the corresponding performance curve of the pump and thus to identify a possible drift of the operating point with respect to the pump performance curve and with respect to the previously defined first reference service point 41.

Depending on the evolution of the drifting trend, it is possible to interpret the probable causes of this drift as shown in FIG. 5 and to detect a possible malfunction.

Figure 5 shows a zonal division of the space in two dimensions defined by the flow rate of the pump and the total head. The division into zones uses the first performance curve of the pump 40 as well as the first reference service point 41. In FIG. 5 is also shown the characteristic curve 50 of the pumping station 1.

A first zone 51 is positioned under the first performance curve of the pump 40 and above a line of constant nanometric height equal to the nanometric height of the first reference service point 41. The first zone 51 is called zone increase the HMT and decrease the flow rate of the pump.

A second zone 52 is defined for all the operating points whose total head is less than the head of the first reference service point 41 and therefore for a flow rate of the pump lower than the flow rate of the pump at the first reference point. 41. The second zone 52 is said zone of decrease of the HMT and decrease of the flow rate of the pump. A third zone 53 is defined below the performance curve of the pump 40, for the service points whose flow rate is greater than the flow rate of the pump at the first reference point 41. The third zone 53 is called the reduction zone of the pump. HMT and rate increase.

A fourth zone 54 is defined for all operating points above the characteristic curve of the pump station. The fourth zone 54 is called the performance increase zone.

Depending on the position of the current service point in one of these zones or on the performance curve of the pump 40 or on the performance curve of the pumping station 50, a different analysis, giving different interpretations to the drift, is realized. For example, a drift from the service point of the pump in the fourth zone 54 may mean that the diameter of the pump wheel has been changed and in particular increased, or that the speed of rotation has increased or both. A preventive action can then be to update the characteristics of the pump in the database.

Another example: if the service point drifts on the pump's performance curve, this may mean that the discharge, or distribution network downstream of the pump, becomes clogged in the case of a drinking water pump. . Another interpretation may be that the drilling plugs in the case of a drilling pump. Obviously the phenomena can be combined. This may also indicate a leak in the discharge lines or the water distribution system. It is also possible that there is a change of dimension leading to the modification of the geometrical height of the pumping station. It will then be recommended to check the pumping station, lines and systems upstream and downstream of pump 20.

In addition, to confirm or refute this pre-diagnosis, it may be recommended, as a preventive measure, to control the relationship between the discharge pressure and the flow, to monitor the damage on the pipes of the system served by the pumping station 1 and the modifications made to the pumping station 1 in order to update the characteristics of the pumping station 1 in the database. The ninth step 39 is a step of creating a history of the various points of service of the engine, determined during the operation of the pumping station 1. The evolution of the service point of the engine is evaluated from a situation reference as shown in FIG. 6.

FIG. 6 illustrates a reference situation that can be used to analyze the possible drifts of the service point of an engine 21.

In FIG. 6, the abscissa represents the mechanical power of the motor.

A first curve 61 represents the intensity of the electric current called. A second curve 62 represents the called active electrical power. A reference service point is defined on each curve 61, 62 for a mechanical power 63 delivered by the engine in the reference situation. It is thus possible to determine an intensity called for the reference service point 64. Then, it is also possible to determine an active electrical power 65 called for the reference service point, for the mechanical power delivered by the engine to the point reference service.

Other trend curves can be used, such as the motor temperature as a function of the current intensity or the motor temperature as a function of the active power, in order to describe the reference situation for monitoring the operation of the motor. .

The tenth step 300 is a step of analysis of a possible drift of the service point of the engine 21 and an interpretation of the drift if it is noted in order to detect a possible malfunction. The analysis is based on an interpretation of the engine load as shown in Figure 7.

Figure 7 shows different load curves on the motor shaft as a function of the speed of rotation of the motor shaft. We define a maximum torque that allows to define a maximum torque speed below which the machine may call. Above this maximum torque speed, the motor 21 is in a stable use area. In this stable use area, or useable stable area, three characteristic curves of different engine loads are defined. A first load curve describes the load in accidental operation of the motor, or accidental load. A second load curve describes the nominal load. A third load curve describes the motor load when the machine runs idle. The intersection of these load curves with a curve defining the evolution of the engine torque as a function of its speed 71, gives the speeds corresponding to each type of load, accidental, nominal or empty.

When the pump wheel rotates without propelling liquid, which may be the case with a clogged wheel or a defused pump, the wheel does not produce hydraulic power. The motor then drives a free wheel and does not need a lot of electrical power. The motor torque drops below torque at rated load. In this case, it is useful to associate the called intensity and the motor torque and to define a low threshold value for the called intensity corresponding for example to 95% of the average intensity at the rated load. If the low threshold is exceeded and the motor enters a range where it runs idle, or at low load, then the pump and its motor should be stopped. One possible interpretation is that there is an air inlet in the pump. The shutdown of the motor and the pump can be automatically implemented by the electrical cabinet 3 of the pumping system 2.

When the pump wheel rotates but is slowed in its rotation, for example: in case of mechanical games clogged with debris, in case of clogging by concretions, in case of start seizing the stop on a pump drilling, then the pump wheel produces a hydraulic power necessary to render the service that is expected but the electric motor delivers on the one hand the mechanical power that is converted into hydraulic power and, on the other hand, an increase in power which counterbalances the braking experienced by wheel. The motor torque rises above the torque at rated load and goes into accidental load. In this case too, it is necessary to couple the analysis of the intensity called, by defining a high threshold beyond which it is estimated that the motor operates in overload. The crossing of the high threshold associated with a motor torque corresponding to an accidental load requires a shutdown of the pump and the motor, as a curative. This stop can be implemented by the management device of the pumping system, comprising the electrical cabinet 3 and the supervision system 7.

Another malfunction can be detected by an increase in active power and a simultaneous loss of HMT. The active electric power called by the motor increases when the suction of the pump is strangled because it is placed in a situation comparable to that of an NPSH test. At a certain point in the throttling of the suction, the total head of the pump can drop and, at the same time, the efficiency of the motor drops and the electric power increases. It is then proposed to set a threshold greater than the active power called by the pump motor. As an indication, this threshold can be set between 102% and 105% of the average active power at the rightmost service point of the pump's service range on the pump's performance curve. It is also necessary to check the following trendlines:

- absolute pressure given as a function of time for a given flow;

- HMT as a function of time;

- active electric power as a function of time;

- engine temperature as a function of time.

An increase in the concomitant active electrical power at a drop in HMT and a decrease in suction pressure means that the suction of the pump clogs and the pump cavity. The increase in engine temperature expresses the imminent threat of overheating of the windings, or windings, of the engine. Immediately stop the pump and carry out a detailed inspection of the suction pump, ie strainer 25, piping, water intake, etc.

The eleventh step 301 is a step of controlling the submergence of the water intake of the pump. This step requires the following measured physical quantities:

- a water level in a suction tank or in the water intake of the pump;

- a flow sucked by the pump to the water intake;

- the geometry, or physical description of the intake according to the following parameters: diameter, position in the water intake or in the suction tank.

In order to analyze the evolution of the submergence, it is necessary to carry out the following calculations:

- calculate the average speed of the flow then the number of

Froude of the flow in the inlet section of the suction pipe and the ratio between the submergence and the diameter of the inlet section of the suction pipe given according to the Froude number (see the condition of submergence of the opening of the suction pipe according to J. Knauss and the condition of submergence of the opening of the suction pipe according to the Hydraulic Institute);

- knowing the ratio between the submergence and the diameter of the inlet section of the suction pipe, the value of the sub- mergence can be calculated.

The analysis of the calculated submergence taking into account in particular the thickness of the water slice in the water intake makes it possible to determine if a swirling flow disturbs the velocity field at the inlet of the pump and if causes an air supply to the pump which could cause a defusing of the pump or at least vibrations of the pump. In this case, it is necessary to raise the water level above the water intake, for example by reducing the flow of the pump or by stopping the pump for curative purposes. A twelfth step 302, 303 may be a step of analyzing a characteristic curve of the discharge 302 and a step of interpretation 302 and pre-diagnosis 303 of a possible drift using the following measured or calculated physical quantities. :

- pressure at the discharge of the pump;

- flow served by the pump;

- intensity called by the motor;

- active power called by the motor.

The analysis is also based on the time evolution of the discharge pressure with respect to the flow rate served by the pump.

It is also possible to take into account mechanical quantities such as vibration levels.

Several indicators can be monitored to detect a blockage problem in the discharge pipe. A first indicator is the service flow that flows through the discharge line. Indeed, a loss of flow causes a reduction in the diameter of the discharge pipe. Depending on the reduction of the diameter which is determined, it may be necessary to carry out a cleaning action of the pipe for curative purposes. Another indicator may be a ratio between the pump's operating flow rate and the flow rate at a point of best pump performance determined on the pump performance performance curve.

It may also be possible to analyze the flow loss of the pump associated with the loss of flow of the pipe to undertake cleaning actions of the discharge pipe.

The thirteenth step 304, 305 is a step of analyzing a possible drift of the characteristic curve of the suction 304, a step of interpretation of this drift and then a pre-diagnosis 305 of a dysfunction of the pipe. suction on detection of an anomaly. The thirteenth step 304, 305 is optional for submerged pumps, that is to say those that are not connected to a water intake via a suction pipe. The measured physical quantities taken into account for the thirteenth step 304, 305 are the following:

- suction pressure of the pump;

- flow served by the pump;

- intensity called by the motor;

- active power called by the motor.

The calculated physical quantities taken into account are the following:

the evolution curve of the suction pressure, measured at absolute pressure, as a function of the flow rate of the pump over time;

the evolution curve of the available N PSH or the suction pressure expressed in absolute pressure as a function of time;

- the evolution curve of the HMT as a function of the flow rate served by the pump, over time;

the active power demanded by the motor as a function of the flow rate served by the pump over time.

The analysis and monitoring of the NPSH, the flow of service flowing in the suction line and the ratio between the flow of service and the flow at the point of best performance make it possible to detect a reduction in the diameter of the pipe, a loss flow rate at the pump and a loss of flow at the pipe that may lead to actions to clean the suction line.

The fourteenth step 306 is a step of pre-diagnosis of the probable causes of malfunctions of the pump. This step is a step to link several indicators of hydraulic failures to possible hydraulic causes to these failures. The indicators considered for this pre-diagnosis stage result from the analyzes previously carried out. These indicators are the following operating conditions: no flow, insufficient flow, insufficient pressure, intermittent flow. Possible causes are for example "the pump is not not initiated or loses its priming "when all of the aforementioned operating conditions are met, or" too much air is trapped in the pumped liquid ", an absence of flow alone may indicate a" clogged wheel ", insufficient flow alone may indicate incorrect direction of rotation of the pump wheel, etc.

The fifteenth step 307 is a pre-diagnosis assistance step on the probable causes of engine failures. In particular, this step makes it possible, starting from a list of failures, to go back to the probable mechanical causes of these failures. The identified failures can be for example the following:

- the bearings are hot or fail very regularly;

- faults on the fittings are very frequent;

the motor braids have a short life;

- the pump vibrates above the allowable levels;

- the pump calls too much power on the shaft;

- the wear of wet parts inside the engine is faster than normal.

For example, if the only failure identified is "the bearings are hot or fail very regularly" then the probable cause may be inadequate cooling of the lubricant or axial or radial load greater than the design load of the bearings of the engine. Another example, a single fault type "faults on the linings are very common" may be related to overheating of the friction faces of the lining or lack of leaching water on the friction faces of the lining or a incorrect fitting of the trim, etc.

A sixteenth step 308 is a step making it possible to establish a link between the evolution of an N PSH and the phenomenon of cavitation of the pump in order to detect the latter. The measured physical quantities necessary to establish this link are as follows:

- for the pump: suction pressure, discharge pressure, flow rate; - for the motor: active electric power, temperature of the windings.

The calculated physical quantities taken into account are the following:

- for the pump: total head, service point and its variation range (flow torque - total head);

- for the pumping station: NPSH available from the pumping station in the range of the service point of the pump. The available N PSH depends on the suction circuit and the suction flow, while the N PSH required by the pump depends on the pump and the flow it delivers. For a given suction circuit and pump, there is a maximum permissible flow rate beyond which the NPSH required by the pump exceeds the N PSH available in the suction circuit. If the flow rate at the service point exceeds this maximum admissible flow rate, the pump may be the seat of the cavitation phenomenon that may damage the pump: cavitation exposes the pump to erosion which can destroy the pump impeller and lead to replacement of the pump, in particular by another type of pump better adapted to the operating conditions. The appearance of this phenomenon may be a sign that the pump used is not suited to the service requested.

A seventeenth step 308 is a step of controlling the energy performance of the pumping unit.

By making a difference between monitoring the overall performance of the pumping system and the reference curve of the pumping system, if a downward trend is identified, this may be due to overall wear of the pumping system.

The wear of the pumping system can also be detected with a monitoring of the specific energy consumption of the pumping system and in particular if there is a statistical difference upwards.

Advantageously, the device and the method according to the invention make it possible, as soon as possible, to detect anomalies in the operation of the pumping station and implement preventive or curative actions to avoid or minimize the consequences of anomalies on the operation or integrity of pumping system. Thus the pumping system is maintained in operational state, that is to say in a state of good operation, efficiently and inexpensively.

The various embodiments of the present invention comprise various steps. These steps can be implemented by instructions of a machine executable by means of a microprocessor for example.

Alternatively, these steps can be performed by specific integrated circuits including logic wired to perform the steps, or by any combination of programmable components and custom components.

The present invention may also be provided in the form of a computer program product which may comprise a non-transitory computer memory medium containing executable instructions on a computer machine, which instructions may be used to program a computer (or any other device electronic) to execute the method.

Claims

1. A method for maintaining in operational condition (30) a pumping system (2) forming part of a pumping station (1), said pumping system (2) comprising a pump (20), a motor (21). ) driving the pump (20), a fluid delivery pipe through the pump (20), a fluid suction pipe through the pump (20), said method being characterized in that it comprises at least the following steps :

measuring physical quantities characteristic of the operation of the pumping system (2), including physical quantities characteristic of the state of the delivery pipe of the pump (20), the state of the suction pipe of the pump (20);

- analysis and interpretation of physical quantities measured to detect one or more anomalies;

- pre-diagnosis of the probable causes of the anomalies detected and determination of the preventive and curative actions to be carried out on the pumping system (2);

- automatic implementation of preventive and curative actions on the pumping system (2).

2. Method according to claim 1, characterized in that it comprises a step of analyzing and interpreting the operating characteristic curves of the suction pipe (304) and delivery (302) of the pump (20) and a submergence control step (301) of a water inlet intake of the pumping system (2).

3. Method according to any one of the preceding claims, characterized in that it comprises a step of analysis and interpretation of the evolution of operating points (38) of the pump (20) and a step analyzing and interpreting the evolution of operating points of the engine (300).

4. Method according to any one of the preceding claims characterized in that it comprises a step of controlling the energy performance (309) of the pumping system (2).

5. Method according to any one of claims 2 to 4, characterized in that it comprises a step of detecting a cavitation phenomenon (308).

6. Method according to claim 2 and according to any one of claims 3 to 5, characterized in that the submergence control step of the intake (301) takes into account a height of water in the intake, a flow sucked by the pump (20) at the intake, physical description parameters of the water intake.

7. Method according to claim 2 and according to any one of claims 3 to 6, characterized in that the step of analyzing and interpreting the operation of the discharge pipe (302) takes into account the evolution in the time of the following parameters: a pressure at the pump discharge, a flow rate served by the pump, a current intensity called by the motor, an active power called by the motor.

8. Method according to any one of claims 2 to 7, characterized in that the step of analyzing and interpreting the operation of the suction line (304), takes into account the evolution over time of the following parameters: a suction pressure of the pump, a flow rate supplied by the pump, a current intensity called by the motor (21), an active power called by the motor (21), a total head, a PSH N available.

9. Device for maintaining in operational condition a pumping system (2) forming part of a pumping station (1), said pumping system (2) comprising a pump (20), a motor (21) driving the pumping system (2). pump (20) and at least one discharge pipe and a fluid suction pipe through the pump (20), said device being characterized in that it comprises:

- Hydraulic and mechanical sensors performing measurements of hydraulic and mechanical quantities on the pump (20), the discharge pipe, the suction pipe;

electrical and mechanical sensors making measurements of electrical and mechanical quantities on the motor (21);

an electrical cabinet (3) for the pumping system (2) collecting the measurements of the hydraulic, electrical and mechanical sensors, transmitting operating instructions to said pumping system (2);

a supervision system (7) comprising a computer on which runs a central program (8) implementing the method for maintaining in operational condition a pumping system (2) according to any one of the preceding claims, said supervision system (7) being able to automatically transmit commands to the electrical cabinet (3) according to the results of analysis, interpretation and pre-diagnosis, said supervision system (7) comprising a human interface -Machine display of analysis results, interpretation and prediagnosis.