EP4386150A1 - Method for obtaining information in a waste water pump unit and/or a waste water pump system - Google Patents

Abstract

The invention relates to a method for obtaining information, in particular for condition monitoring, in a wastewater pump unit (2) of a wastewater pump system (1) and/or in a wastewater pump system (1) comprising at least one wastewater pump unit (2, 2a), wherein the wastewater pump unit (2, 2a) pumps wastewater (4) out of a container (3) for collecting the wastewater (4) during operation. In this case, with the aid of a separate sensor (14), an externally measurable physical quantity of the wastewater pump unit (2, 2a) and/or system (1) is recorded, the switch-on time (t_on) and the switch-off time (t_off) of the wastewater pump unit (2, 2a) are determined from the recorded quantity, and an operating time (T_on) or operating break time (T_off) is calculated therefrom, which is then evaluated in order to obtain at least additional information about the wastewater pump unit (2, 2a) and/or the wastewater pump system (1).

Description

The invention relates to a method for obtaining information, in particular for condition monitoring, in a wastewater pump unit of a wastewater pump system and/or in a wastewater pump system comprising at least one wastewater pump unit, wherein the wastewater pump unit, during operation, pumps wastewater out of a container for collecting the wastewater.

Wastewater pump systems collect wastewater, for example rainwater, surface water, process water, grey water and/or black water, in a container. The wastewater is pumped out by at least one corresponding wastewater pump unit as soon as it reaches a certain maximum level in the container, which is measured by a level sensor in or on the container, for example a float. Such wastewater pump systems are also known as lifting systems. Once the maximum level is reached, the wastewater pump unit is switched on. It is switched off again when a certain minimum level is reached. Wastewater pump units are therefore only operated when required and for comparatively short operating times, for example half a minute to a few minutes. The operating times for a specific wastewater pump system are always the same after commissioning, since the volume of wastewater that has to be pumped out, defined by the maximum and minimum levels, is constant. The wastewater pump unit is usually operated unregulated, i.e. at a constant speed.

The increasing wear of the sewage pump unit over time, particularly the bearings and/or the impeller, deposits on the impeller or pump housing and/or a blockage of the suction or discharge opening of the sewage pump unit result in a gradual or spontaneously sharp increase in the operating time. At the same time, deposits in the container lead to a reduction in the operating time, as the effectively pumpable volume becomes smaller. The operating time is therefore an indicator of the condition of a sewage pump system, or rather its sewage pump unit.

It is generally known that a relatively complex measurement and evaluation technology with one or more sensors is used to monitor the condition of pump units. For example, to detect a blockage in a wastewater pump unit, its operating point is continuously monitored for a certain change. For this purpose, sensors are used, for example, to record hydraulic variables such as the differential pressure generated by the pump and/or the pumped volume flow, or sensors to record electrical variables such as the current consumption, the input and/or output voltage and/or the power consumption. Alternatively, a blockage can be detected based on vibrations in the wastewater pump unit, which are recorded using acceleration sensors. In some cases, several sensors are usually required to obtain specific information, especially about a specific condition.

In the case of analog signals, the measurement signals from such sensors are regularly amplified, filtered and digitized if necessary, and then evaluated. Digital signals are also usually filtered to improve the signal-to-noise ratio, and then evaluated, for example by comparing them with a limit value or by performing a frequency analysis.

It goes without saying that for the purposes mentioned, both the necessary sensors and the necessary electronics for processing and evaluating the sensor signals to obtain the desired information are comparatively complex, expensive and time-consuming to install or integrate into the sewage pump unit or sewage pump system. If the Due to the lack of functionality for obtaining the desired information from the sewage pump unit or the sewage pump system, retrofitting is either not possible at all or only possible with considerable effort and expense.

It is an object of the present invention to provide a technically very simple, cost-effective and retrofittable possibility of obtaining at least one desired additional information in a wastewater pump unit or a wastewater pump system with at least one wastewater pump unit.

This object is achieved by a method having the features of claim 1. Advantageous further developments are specified in the subclaims and are explained below.

1. a) mit Hilfe eines separaten Sensors, eine von außen messbare physikalische Größe des Abwasserpumpenaggregats und/oder des Abwasserpumpensystems erfasst wird,
2. b) aus der erfassten Größe der Einschaltzeitpunkt und der Ausschaltzeitpunkt des Abwasserpumpenaggregats ermittelt wird,
3. c) aus dem Einschaltzeitpunkt und dem Ausschaltzeitpunkt eine Betriebsdauer oder Betriebspausendauer berechnet wird, wobei der Sensor dazu verwendet wird, den Einschaltzeitpunkt und den Ausschaltzeitpunkt des Abwasserpumpenaggregats zu ermitteln, und
4. d) die Betriebsdauer oder die Betriebspausendauer ausgewertet wird, um wenigstens eine Mehrinformation über das Abwasserpumpenaggregat und/oder das Abwasserpumpensystem zu erhalten.

According to the invention, it is proposed to further develop the generic method in such a way that

1. a) by means of a separate sensor, an externally measurable physical quantity of the sewage pump unit and/or the sewage pump system is recorded,
2. b) the switch-on time and switch-off time of the sewage pump unit are determined from the measured value,
3. c) an operating time or operating break time is calculated from the switch-on time and the switch-off time, whereby the sensor is used to determine the switch-on time and the switch-off time of the sewage pump unit, and
4. d) the operating time or the operating break time is evaluated in order to obtain at least additional information about the waste water pump unit and/or the waste water pump system.

The switch-on time of the sewage pump unit is, depending on the type of sensor used or the type of physical quantity measured, the time at which it starts to pump or at which the drive motor of the sewage pump unit is energized, or at which an electromagnetic field exists or rotates in the drive motor, or at which the Rotor or the pump impeller begins to rotate or vibrations occur. Similarly, the switch-off point of the sewage pump unit is the point in time at which it stops pumping or at which the drive motor of the sewage pump unit is no longer energized or at which an electromagnetic field in the electric motor no longer rotates or at which the rotor or the pump impeller has stopped rotating or vibrations stop.

Depending on the sensor used, the times mentioned can differ by a few milliseconds to seconds. For example, the energization of the electric motor indicates the earliest time that can be considered the switch-on time. The energization immediately leads to an electromagnetic field in the drive motor, so that the build-up or sudden existence of such an electromagnetic field can also be considered the switch-on time. After overcoming the inertia of the mass, the rotor begins to rotate a few hundred milliseconds later as a result of the torque acting on it through the field, so that alternatively the start of rotation can also be considered the switch-on time. The rotor then gradually increases until the operating speed is reached. This can take a few seconds. As a result of the rotation of the rotor and the impeller, the sewage pump unit generates vibrations that can be detected on its housing (pump and/or motor housing) and are noticeable from a certain speed. The switch-on time can therefore also be considered to be the time at which vibrations become measurable or exceed a limit value. From another specific speed, the sewage pump unit pumps, so that according to a further alternative, the switch-on time can be considered to be the time at which the volume flow is greater than zero or greater than a limit value.

According to these switch-on times, the switch-off times can also differ by a few milliseconds to seconds. For example, switching off the power supply to the drive motor represents the earliest time that can be considered as the switch-off time. Switching off the power supply immediately leads to the reduction of the electromagnetic field in the drive motor, which can be considered as the switch-off time. However, in the case of a permanent magnet rotor, and as a result of the remanence also in the case of an induction motor, a magnetic field continues to rotate due to the continued rotation of the rotor, so that alternatively the switch-off time can be considered to be the time at which the field no longer rotates. This only happens when the rotor comes to a standstill, to which it is braked due to mechanical and hydraulic friction, which can take several seconds. The constantly decreasing speed also reduces the vibrations and the volume flow. According to a further alternative, the switch-off time can therefore also be considered to be the time at which vibrations are no longer measurable or are below a limit value, or at which the volume flow is no longer measurable or is below a certain limit value, i.e. the sewage pump unit no longer pumps.

Although the switch-on times and switch-off times mentioned can each be different in relation to an absolute reference time, the exact switch-on time and the exact switch-off time are not important within the scope of the invention, since they are related to each other to determine the operating time or operating break time. The only important thing is that the type of measurement of the switch-on time and the switch-off time does not change.

The operating time is the difference between the switch-off time and the previous switch-on time. Accordingly, the operating break time is the difference between the switch-on time and the previous switch-off time.

A wastewater pump unit is a pump unit that is designed to pump wastewater such as rainwater, surface water, process water, grey water and/or black water from a container that is used to collect the wastewater. The wastewater may contain bulk goods.

A pump unit comprises a pump unit, an electric motor which drives this pump unit directly or via a clutch and/or a gear, and drive electronics which energise the electric motor, in particular controls and/or or regulates. The pump unit, the electric motor and the drive electronics can form a structural unit or be installed spatially separate from one another.

The pump unit is preferably designed in the form of a centrifugal pump. The electric motor can be a three-phase motor, preferably an electronically commutated synchronous motor. The motor shaft and the pump shaft are suitably one-piece, so that the free end of the motor shaft opposite the electric motor carries the pump impeller. The drive electronics can comprise a frequency converter.

It can be provided that in step d) the operating time, or an operating variable determined therefrom, is compared with a reference operating time or a reference variable, with the result of the comparison being used to determine the state, in particular a fault state, of the wastewater pump unit and/or the wastewater pump system. The additional information is therefore information about the state of the wastewater pump unit and/or the wastewater pump system. The calculated operating time is the current operating time of the wastewater pump unit.

According to one design variant, the reference operating time can be an earlier operating time of the wastewater pump unit. This earlier operating time can be determined, for example, when the wastewater pump unit or the wastewater pump system is first put into operation. Alternatively, a standard operating time can be used as the reference operating time. The standard operating time can be the operating time that is required in fault-free normal operation of another wastewater pump unit of the same design at a certain operating speed, for example nominal speed, to empty the container from a maximum water level to a minimum water level. This standard operating time can have been determined at the manufacturer's factory and can be representative of all pump units of the same design as the wastewater pump unit.

By comparing the actual operating time required with the reference operating time, it can be determined whether and to what extent the The operating condition of the sewage pump unit and/or sewage pump system has deteriorated or has deteriorated. For example, a faulty condition in the form of a blockage, bearing or impeller damage to the sewage pump unit or a blockage in a pressure line connected to it can be concluded if the calculated operating time is greater than or greater than the reference operating time by a limit value. Alternatively or cumulatively, a faulty condition in the form of a deposit, in particular an accumulation of sediment in the container, can be concluded if the calculated operating time is less than or less than the reference operating time by a limit value.

As an alternative to comparing the calculated operating time with the reference operating time, an operating variable can first be calculated from the operating time and then compared with the value of a reference variable in order to obtain additional information.

For example, the operating variable can be a theoretical volume of wastewater pumped by the pump unit, which is obtained by multiplying the determined operating time by an expected pumping capacity in volume per unit of time, e.g. in l/min or m ³ /min. The expected pumping capacity can be the nominal capacity that a wastewater pump unit of the same design as the wastewater pump unit has in fault-free normal operation at a certain operating speed, e.g. nominal speed, and which can be determined by the manufacturer at the factory. The reference variable is then also a volume, in particular the partial volume of the container that results from multiplying the difference between the maximum water level and the minimum water level by the base area of the container. In this design variant, two volumes are compared with each other instead of operating times.

If the operating time is extended, the value of the calculated operating variable, in this case the pumped volume, would also increase. However, since the pumped volume cannot be larger than the partial tank volume specified by the reference variable, the comparison of the calculated operating variable with the reference variable provides additional information that the condition of the pump unit has deteriorated or has deteriorated if the calculated operating variable is or becomes greater than the reference variable. For example, a faulty condition in the form of a blockage, bearing or impeller damage to the wastewater pump unit or a blockage in a pressure line connected to it can be concluded if the calculated operating variable is greater than or greater than the reference variable by a limit value. Alternatively or cumulatively, a faulty condition in the form of a deposit, in particular an accumulation of sediment in the container, can be concluded if the calculated operating variable is less than or less than the reference variable by a limit value.

In one embodiment, the operating time or operating break time is repeatedly calculated according to steps a) to c) each time the wastewater pump unit is operated. A trend is then determined from the calculated operating times or operating break times, which forms the operating variable. In this embodiment, the operating variable therefore indicates whether, in which direction and to what extent the operating time or operating break time changes over time. The reference variable can form a limit value for the trend. A faulty condition in the form of a blockage in the wastewater pump unit, a bearing or impeller defect in the wastewater pump unit or a blockage in a pressure line connected to it can be concluded if the trend in the operating time is positive and exceeds the limit value in terms of amount. Alternatively or cumulatively, a faulty condition in the form of a deposit, in particular an accumulation of sediment in the container, can be concluded if the trend in the operating time is negative and falls below the limit value in terms of amount.

It can be provided that the wastewater pump system comprises at least a second wastewater pump unit. The pumping task is typically the same for both wastewater pump units, namely to pump a certain volume, usually triggered by a level sensor.

Preferably, steps a) to c) are also carried out on the second sewage pump unit in order to calculate its operating time and to evaluate it to obtain additional information. As with the first wastewater pump unit, the calculated operating time of the second wastewater pump unit can also be compared with the or a corresponding reference operating time in order to use the result of the comparison to draw conclusions about the condition, in particular a fault condition, of the second wastewater pump unit and/or the wastewater pump system. In this case, too, the reference operating time can be an earlier operating time, more precisely an earlier operating time of the second wastewater pump unit. In particular, this earlier operating time can be the one that existed or was determined when the second wastewater pump unit was first put into operation. Furthermore, the standard operating time can also be used here as an alternative as the reference operating time.

Likewise, in another embodiment, as in the case of the first wastewater pump unit, an operating variable can first be determined from the operating time of the second wastewater pump unit and this can be compared with the reference variable in order to use the result of this comparison to draw conclusions about the condition, in particular a fault condition, of the second wastewater pump unit and/or the wastewater pump system. In this case, too, the operating variable can be a volume, for example, as was previously described with regard to the first wastewater pump unit. Accordingly, the reference variable is also a volume. In this regard, reference is also made to the explanations for the first wastewater pump unit.

According to another embodiment, in which the first and second wastewater pump units are of identical construction, the operating times of the first and second wastewater pump units, or the operating variables calculated from them, can be compared with each other. This makes it possible to qualitatively evaluate the condition of one wastewater pump unit in relation to the other pump unit, in particular to detect a faulty condition.

If the pumped volume is used as the operating variable, it is not even necessary for the sewage pump units to be identical. This is because the volume can be calculated by multiplying the respective operating time by a pump-specific Pump performance can be calculated in volume per unit of time. In this case, the operating variables determined from the operating times must be compared with each other.

The reference operating time used in the comparison with the operating time of the first sewage pump unit can in this case be the calculated operating time of the second sewage pump unit. Conversely, the reference operating time used in the comparison with the operating time of the second sewage pump unit can in this case be the calculated operating time of the first sewage pump unit. Accordingly, the reference variable used in the comparison with the operating variable calculated from the operating time of the first sewage pump unit can in this case be the operating variable determined from the operating time of the second sewage pump unit. Analogously, the reference variable used in the comparison with the operating variable calculated from the operating time of the second sewage pump unit can in this case be the operating variable determined from the operating time of the first sewage pump unit. Of course, in this case the operating variables must be determined in the same way.

The second wastewater pump unit can be arranged in a second container or connected to it in order to pump wastewater out of the second container, whereby the first wastewater pump unit pumps wastewater into the second container via a wastewater line during operation. It is therefore possible for the first and/or second wastewater pump unit to be a submersible pump inside the respective container, or a dry-installed pump outside the respective container. In addition, one of the two pumps can be arranged in the corresponding container and the other pump outside the corresponding container. In these cases, the wastewater line is connected to the pressure line of the first wastewater pump unit and forms the inlet line to the second container. In other words, the two wastewater pump units are hydraulically arranged one behind the other, or in other words, in series. The first and second containers, the wastewater line and the two wastewater pump units are part of the wastewater pump system.

Leaks are a major problem in such wastewater pump systems. Measures can be provided to detect possible leaks. Flow sensors are usually used for this purpose, which are expensive and require a lot of maintenance. To overcome this disadvantage, it can be provided that the sum of the operating times of the first wastewater pump unit in a certain period of time is calculated and used as the operating variable and the sum of the operating times of the second wastewater pump unit in the period of time is calculated and used as the reference variable, and that a fault in the wastewater pump system in the form of a leak in the wastewater line is concluded if the operating variable is greater than or greater than the reference variable by a limit value.

The core idea of the measure mentioned is that with pumps that run in a serial configuration, it is to be expected that each pump will pump the same amount of volume, at least on average over a period of time under consideration. Instead of measuring the exact flow, the method according to the invention determines a possible leak by comparing the sum of the operating times of the pumps connected in series over a period of time under consideration. If the sum of the operating times of the first wastewater pump unit in the activity period is greater than the sum of the operating times of the second wastewater pump unit, a leak can be concluded. Thus, in one embodiment, the respective operating size of the first and second wastewater pump units can be the sum of the operating times of the operations of the respective wastewater pump unit carried out in a common activity period. Thus, it is easy to determine, solely on the basis of the use of ON/OFF information from the individual pumps, whether the wastewater pump system is in a faulty state, or more precisely whether the wastewater line is damaged and wastewater is flowing uncontrollably and unintentionally into the environment.

There are sewage systems in which surface water, such as rainwater, on the one hand, and grey and/or black water on the other hand, are transported separately from each other in order to reduce the amount of water to be treated for the Sewage treatment plant or wastewater treatment plant to limit the flow of grey and/or black water. However, there are always cases in which private drainage pipes, which also carry rainwater, illegally flow into the grey or black water part of a public sewage system that uses the separation concept described. In order to detect such an impermissible inflow of rainwater, the operating times or operating sizes of the first and second sewage pump units can also be compared with each other or with the reference operating time or reference size and evaluated.

It can therefore be provided according to the invention that the sum of the operating times of the first wastewater pump unit in a certain observation period is formed and used as the operating variable and the sum of the operating times of the second wastewater pump unit in the observation period is formed and used as the reference variable, and that a fault in the wastewater pump system in the form of an impermissible inflow into the sewage line is concluded if the operating variable is less than or less than the reference operating time or the reference variable by a limit value.

According to a further development, in a serial configuration of two wastewater pump units, it can be provided that, after assuming an impermissible inflow into the wastewater line, a database with weather data about the installation location of the wastewater pump system is queried and it is determined whether there is a correlation between the operating time or operating size and the precipitation that has occurred at the location of the wastewater pump system. In this way, it can be determined whether rainwater is entering the system.

The described inflow detection and leakage detection for sewage pump units arranged hydraulically one after the other can be used alternatively or cumulatively.

In one embodiment of the method according to the invention, the second sewage pump unit can be operated together with the first Wastewater pump unit can be arranged in the container or connected to it. In this design variant, the two pumps can therefore be either submersible pumps for arrangement in the container or dry-installed pumps outside the container. In addition, one of the two pumps can be arranged in the container and the other pump outside the container. This is for redundancy, so that in the event of a defect in one wastewater pump unit, the other wastewater pump unit can be used. In practice, the two wastewater pump units are not operated simultaneously, but alternately, in order to achieve even wear on the wastewater pump units. In other words, the two wastewater pump units in this design variant are arranged hydraulically in parallel.

For such an arrangement, the method according to the invention can be used to conclude that a faulty state in the form of a blockage of the first wastewater pump unit, a bearing or impeller damage to the first wastewater pump unit or a blockage of a wastewater line connected to it is present if the operating time of the first wastewater pump unit or the operating variable derived therefrom is greater than or greater by a limit value than the reference operating time or the reference variable. In this case, the reference operating variable is the operating time of the second wastewater pump unit. Alternatively, the reference variable is derived from the operating time of the second wastewater pump unit. Of course, the reverse case could also be checked in an equivalent manner, namely whether the operating time of the second wastewater pump unit or the operating variable derived therefrom is less than or less by a limit value than the reference operating time or the reference variable, the reference operating variable in this case being the operating time of the first wastewater pump unit and/or the reference variable being derived therefrom.

In one embodiment, the additional information can be the wastewater volume pumped by the wastewater pumping unit, which is determined in step d) from the operating time. As already mentioned, the pumped wastewater volume can be determined by multiplying the operating time by a pumping capacity (volume per unit of time) which occurs during normal operation (nominal operation) of the sewage pump unit after it is switched on.

As an alternative to the operating time, the operating break duration can be calculated in step c) and evaluated in step d) in order to obtain at least one additional piece of information about the wastewater pumping system. In such an embodiment, the additional information can be, for example, information as to whether there is an impermissible inflow into the wastewater pumping system. As already mentioned, such an impermissible inflow occurs, for example, when rainwater enters the wastewater pumping system which is not intended to carry rainwater. If steps a) to c) are repeated and the operating break duration calculated in each case is compared with a reference break duration in step d) or an operating break size determined from the operating break duration(s) is compared with a reference break size, it can be concluded that there is a faulty state in the form of an abnormal inflow of water into the wastewater pumping system if the operating break duration is repeatedly less than or less than the reference break duration by a limit value.

In the same way, the aforementioned comparison can be used to determine whether a wastewater pumping system that transports rainwater is insufficiently small. If the operating break duration during a rain event is repeatedly less than the reference break duration, and heavier rain events are expected in the future, an alarm can be triggered and the operator informed of the inadequate dimensioning. It is therefore also advantageous in this respect to query weather data, correlate it with the abnormal behavior identified by the comparison according to the invention, and gain further knowledge from it, in particular to send alarm or information messages to the operator of the wastewater pumping system.

It is also possible to take a maximum flow rate into account and to set the operating break time in relation to this maximum flow rate. For example, if the maximum flow rate is 50 L/min and the switching volume in the tank (volume between the minimum and maximum levels in the tank) is 500 liters, it will take 10 minutes for the tank to fill up and the Wastewater pump unit is switched on. If this then pumps the wastewater with a flow rate of 200 l/min, it takes around 3 minutes and 20 seconds with a sustained maximum inflow until the minimum level is reached and the wastewater pump unit is switched off. Accordingly, there is an operating break between the switch-off and the restart when the maximum level is reached of 6 minutes and 40 seconds. This operating break can be used as a reference break duration. If the comparison of the determined operating break duration with the expected reference break duration shows that the operating break duration is shorter, this also indicates a fault in the system, e.g. the ingress of rainwater. This is then also additional information gained.

In one version, the reference pause duration can be calculated from completely external variables such as weather data and, if necessary, can also be adjusted dynamically.

In one embodiment, the additional information can be the volume pumped by the wastewater pump unit or the inflow into the container. For this purpose, it can be provided that the operating time is determined from the switch-on time and the subsequent switch-off time, and also the restart time of the wastewater pump unit is determined from the recorded value after an operating break following the switch-off time, and that the operating break duration is calculated from the last switch-off time and the subsequent restart time. This means that there is both an operating time and an operating break duration. In step d), the volume flow of the wastewater pump unit, i.e. the outflow from the container, and/or the inflow into the container, can then be approximately determined from the operating time and the operating break duration.

bestimmt werden.The volume flow of the sewage pump unit can be calculated, for example, according to the equation: $$Q_{\mathit{out}}=\frac{T_{\mathit{on}}+T_{\mathit{off}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

be determined.

bestimmt werden.Furthermore, the inflow into the container can be calculated according to the equation: $$Q_{\mathit{in}}=\frac{T_{\mathit{on}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

be determined.

In the equations, Q _out is the volume flow of the sewage pump unit, T _on is the operating time, T _{off is} the operating break time, A is the cross-section of a cylindrical container, h _{on is} a switch-on level in the container at which the sewage pump unit switches on, and h _off is a switch-off level in the container at which the sewage pump unit switches off. The switch-on level can correspond to the maximum level mentioned above. Furthermore, the switch-off level can correspond to the minimum level mentioned above.

The sensor is suitably connected to an evaluation unit, which evaluates the sensor signal and calculates the operating time and/or operating break time. The sensor can then transmit its sensor signal to the evaluation unit, which then carries out the aforementioned evaluation. In one embodiment, the evaluation unit can also evaluate the operating time and/or operating break time and thus obtain the additional information according to step d). However, step d) is preferably carried out outside the evaluation unit, for example on a remote server, in particular one connected to the Internet. The evaluation unit can transmit the operating time and/or operating break time to this for the purpose of evaluation, in particular via the Internet.

The sensor can also be integrated into the evaluation device. Furthermore, the time of transmission of the operating time and/or operating break time to the server can be triggered depending on the current operating state, e.g. when the sewage pump unit switches off or is switched off. This is useful if the sensor or the evaluation device is installed under water, because then is exposed to a mechanically and hydraulically quieter environment. This is also useful if the sensor or evaluation device is not installed underwater, because data transmission is not affected by interference from the power electronics when the engine is switched off.

It is advantageous if a service message is generated and transmitted to a user when a faulty condition has been detected. The service message can be generated by the evaluation unit or the server, depending on where step d) is carried out.

In the context of the invention, a separate sensor is understood to be a sensor that is structurally independent of the wastewater pump unit, but can be brought together with it in some way, and if necessary also mounted on it, in order to record a physical quantity of the wastewater pump unit. The sensor thus forms a separate component from the wastewater pump unit, which can also be retrofitted if necessary. In other words, the sensor is not a component that is permanently integrated into the wastewater pump unit, but an additional component that spatially supplements the wastewater pump unit or the wastewater pump system, and can preferably also be separated again from the wastewater pump unit or wastewater pump system without causing any damage. However, the sensor is part of the wastewater pump system when installed.

The sensor can be intended exclusively for use in determining the switch-on and switch-off times of the sewage pump unit. In other words, the sensor can be irrelevant for the proper operation of the sewage pump unit. The sensor can neither be a sensor that is required for the regulation and/or control of the sewage pump unit or electric motor, nor is it used for this purpose. Rather, it can form an additional component that provides at least one additional function for the sewage pump unit or the sewage pump system in functional terms, namely non-invasively determining the switch-on and switch-off times of the pump unit. In addition, the sensor can have another function which are, however, irrelevant for the proper operation of the sewage pump unit.

For example, the sensor can be attached, in particular removably, to the outside of the sewage pump unit or to a part of the sewage pump system that is operatively connected thereto, such as the drive motor, the pump unit, a gear, a lantern, a rod, a pressure line or a supply cable of the sewage pump unit.

The sensor can preferably be a vibration sensor, a current sensor or a magnetic field sensor.

The vibration sensor can be an acceleration sensor to detect mechanical vibrations of the sewage pump unit, the existence of which indicates the operation of the sewage pump unit. The sensor can be attached to almost any location on the sewage pump unit or another part of the sewage pump system to which the vibrations are transmitted. With regard to the aspect of retrofitting, the pressure line that is connected to the pressure outlet of the sewage pump unit and carries the pumped wastewater is particularly suitable for locating the sensor. Alternatively, a rod that is arranged in the container and the end of which is firmly connected to the sewage pump unit can be used. The pressure line and rod protrude from the wastewater even at maximum water level and therefore always have dry and easily accessible sections where the sensor can be installed particularly easily and, above all, retrofitted. Due to its dry arrangement, the sensor does not have to be waterproof. IP67 protection of the sensor electronics is sufficient.

The current sensor can be an inductive current transformer in the form of a so-called through-hole transformer. Such a through-hole transformer has a toroidal core that is at least partially wound with a coil, through which the supply cable of the sewage pump unit can be fed. A segment of the toroidal core can be removed to insert the supply cable. In this case, the sensor can also be installed dry and easily retrofitted. During operation, a current flows through the supply cable, which creates a magnetic field around the supply cable, which in turn passes through the toroidal core and induces a voltage in the coil, which in turn can be measured.

The magnetic field sensor can be a reed contact or a coil, which is intended to be arranged on the electric motor of the sewage pump unit in such a way that it detects the magnetic field generated by the electric motor or stator during operation. If a stator field is present, the reed contact closes and a measurable voltage is induced in the coil. Both enable detection of whether the sewage pump unit is switched on or off.

Depending on the sensor used, it can provide a continuous signal (e.g. 0-10V or 0-20mA) or a binary, unsigned (e.g. 0V, 5V) or signed (e.g. ±5V) signal. The switch-on time and switch-off time can be determined, for example, by the signal provided by the sensor exceeding or falling below a signal limit, having a rising or falling edge or changing sign.

Accordingly, it can be provided that the sensor is connected to an evaluation unit which is set up to check the sensor signal to determine whether the signal exceeds or falls below the signal limit, has a rising or falling edge, or has a sign change in order to detect when the sewage pump unit is switched on and off, depending on the sensor used. A sign change can be used if the sensor only supplies a binary signal that is either positive or negative. For example, exceeding the signal limit, the occurrence of a rising edge and/or a positive sign change (from minus to plus) can indicate that the sewage pump unit is switched on, and falling below the signal limit, the occurrence of a falling edge and/or a negative sign change (from plus to minus) can indicate that the sewage pump unit is switched off.

It should be noted that in one embodiment, the reference operating time or the reference size can be determined from external sizes that are available in the cloud or on a server connected to the Internet.

Furthermore, the reference operating time or the reference value can be adjusted dynamically during operation. For example, it can be determined from historical values and form a moving average, i.e. an average that also takes into account the last operating activity of the wastewater pump unit or system.

The operating variable can be, for example, an average value, the trend or the derivative of past operating times. Furthermore, the operating break variable can be, for example, an average value, the trend or the derivative of past operating break times.

Further features, advantages and properties of the invention are explained in more detail below using exemplary embodiments and the attached figures. In the figures, identical reference numbers or symbols designate identical or at least equivalent components, parts, surfaces or directions.

It should be noted that, in the context of this description, the terms "have", "comprise" or "include" in no way exclude the presence of other features. Furthermore, the use of the indefinite article for an object does not exclude its plural.

Features of one embodiment of the invention may also be present in another embodiment, unless this is technically excluded.

Fig. 1 bis 3:

jeweils eine schematische Darstellung eines Abwasserpumpensystems mit einem Abwasserpumpenaggregat und einem Sensor in unterschiedlichen Anordnungen.

Fig. 4:

eine schematische Darstellung eines Abwasserpumpensystems mit zwei Abwasserpumpenaggregaten in einem Behältnis

Fig. 5:

eine schematische Darstellung eines Abwasserpumpensystems mit zwei Behältnissen und jeweils einem Abwasserpumpenaggregat darin

Fig. 6 und 7:

eine Veranschaulichung von Vergleichen einer ermittelten Betriebsdauer T_on mit einer Referenzbetriebsdauer T_on,ref

Fig. 8:

eine Veranschaulichung einer mit der Zeit t ansteigenden, trendbehafteten Betriebsdauer T_on.

Fig. 9:

den allgemeinen Ablauf des erfindungsgemäßen Verfahrens

Show it:

Fig. 1 to 3:

each a schematic representation of a wastewater pumping system with a wastewater pump unit and a sensor in different arrangements.

Fig.4:

a schematic representation of a sewage pumping system with two sewage pump units in one container

Fig.5:

a schematic representation of a sewage pumping system with two containers and one sewage pumping unit in each

Figs. 6 and 7:

an illustration of comparisons of a determined operating time T _on with a reference operating time T _on,ref

Fig.8:

an illustration of a trending operating time T _on increasing with time t.

Fig.9:

the general procedure of the method according to the invention

Figure 1 shows a wastewater pump system 1 comprising a container 3 for collecting wastewater 4, which enters the container 3 via an inlet line 8. A wastewater pump unit 2 is arranged in the container 3 in order to pump the wastewater 4 out of the container 3 via a pressure line 9. For this purpose, the pressure line 9 is connected to the pressure side 7 of the wastewater pump unit 2. The suction side 6 of the wastewater pump unit 2 opens into the area of the container near the bottom in order to suck the wastewater 4 out from there. The wastewater pump unit 2 is therefore designed as a submersible pump here. However, in a variant not shown, it is also possible and sensible to set up the wastewater pump unit 2 outside the container 3. In this case, the suction side 6 extends into the container 3 via a suction pipe. The wastewater pump unit 2 is powered via a supply line 12, which is connected to a controller 10. Also connected to this control 10 is a level sensor 5, which detects the water level 13 in the container 3 and sends it to the control 10 via a measuring line 11. Such a wastewater pump system 1 is known per se. It works autonomously. The control 10 switches the wastewater pump unit 2 on when a switch-on level or maximum level is reached in the container 3 and switches it off again when the wastewater 4 has been pumped down to a switch-off level or minimum level.

In the sewage pump system 1, a method for obtaining information, in particular for condition monitoring, is now used, the steps of which are Figure 9 are mentioned.

According to the invention, a sensor 14 is now provided to detect an externally measurable physical quantity of the sewage pump unit 2, step Sa in Figure 9 . The sensor 14 is in the Figure 1 In the first embodiment shown, the sensor 14 is arranged on the outside of a housing part of the sewage pump unit 2 and is therefore separate from the sewage pump unit 2. The sensor 14 can be screwed onto the housing part, clamped on and/or attached to it via a magnetic holder. The sensor 14 is connected to an evaluation unit 15 via a signal line 19. The evaluation unit 15 is set up to continuously check the detected variable, more precisely the signal from the sensor 14, to determine whether the sewage pump unit 2 has been switched on or off. Depending on the type of sensor 14 or the type of its output signal, this can be done in different ways. If necessary, the evaluation unit 15 can also impress a measuring current into the sensor 14 if required.

The sensor 14 can be a vibration sensor or a magnetic field sensor. In the case of a vibration sensor, the physical quantity of the sewage pump unit 2 is its mechanical vibration, which is generated due to the parts rotating in the sewage pump unit 2. The presence of vibrations is an indicator of the operation of the pump unit. The vibration sensor can be an acceleration sensor. In the case of a magnetic field sensor, the physical quantity of the sewage pump unit 2 is the magnetic field of the stator, which extends as a stray field outside the housing part when the sewage pump unit 2 is in operation. The magnetic field sensor can be a reed contact or a coil. A reed contact is a switch that closes in a magnetic field and a voltage is induced in the coil. The presence of a stray field, thus a closed reed contact or a voltage induced in the coil, are also each an indicator of the operation of the sewage pump unit.

The evaluation unit 15 can process the sensor signal if necessary, e.g. amplify and/or filter it. It then checks whether it exceeds or falls below a limit value, has a rising or falling edge or has a sign change. These events indicate that the sewage pump unit has been switched on and off. In the event of a Vibration sensor, the evaluation unit 15 can be set up to check the sensor signal to see whether it contains an alternating component or whether the amplitude of the alternating component exceeds a certain limit value, which in both cases indicates operation of the wastewater pump unit. Alternatively, depending on the sensor signal, the occurrence of a rising edge and/or a positive change in sign (from minus to plus) can indicate that the wastewater pump unit is switched on, and if the limit value is undershot, the occurrence of a falling edge and/or a negative change in sign (from plus to minus) can indicate that the wastewater pump unit is switched off.

From the detected value, more precisely from the occurrence of certain events in the signal of the sensor 14, the evaluation unit 15 then determines the switch-on time t _on and the switch-off time t _off of the sewage pump unit 2, step Sb in Figure 9 . In the case of a vibration sensor, the switch-on time t _on can, for example, be the time at which an alternating component occurs in the sensor signal or exceeds a limit value. Accordingly, the switch-off time t _off can, for example, be the time at which the alternating component in the sensor signal disappears or falls below the limit value. In the case of a magnetic field sensor in the type of coil, the switch-on time t _on can, for example, be the time at which the sensor signal or the voltage induced in the coil becomes greater than zero or exceeds a limit value. Accordingly, the switch-off time t _off can, for example, be the time at which the sensor signal or the voltage induced in the coil becomes zero or falls below the limit value. In the case of a magnetic field sensor in the type of reed contact, the switch-on time t _on can, for example, be the time at which the sensor signal shows an edge falling from a measuring voltage to OV. Accordingly, the switch-off time t _off can, for example, be the time at which the sensor signal shows a rising edge from OV to a measuring voltage. These are merely examples of possible events in the sensor signal.

The switch-on time t _on and the switch-off time t _off refer to a common reference time t ₀ . A real-time clock can be present in the evaluation unit 15 so that the switch-on time t _on and the switch-off time t _off can be expressed in each case by a time of day. Alternatively, a counter can run in the evaluation unit 15, so that the switch-on time t _on and the switch-off time t _off can each represent a counter reading.

From the switch-on time t _on and the switch-off time t _off, the evaluation unit 15 then calculates an operating time T _on , see step Sc in Figure 9 , if the switch-on time t _on was before the switch-off time t _off , or an operating break duration T _off , if the switch-off time t _off was before the switch-on time t _on . However, the method is sensibly carried out continuously, so that a restart after the sewage pump unit 2 has been switched off or a restart after the sewage pump unit 2 has been switched on is or are recorded, so that both a current operating duration T _on and a current operating break duration T _off are repeatedly calculated.

The operating time T _on is the difference between the switch-off time t _off and the switch-on time t _on : T _on = t _off - t _on . The operating break time T _off is the difference between the switch-on time t _on or the next switch-on time t _on+1 and the last switch-off time t _off : T _on = t _on+1 - t _off .

It should be noted that the sensor 14 is used exclusively to determine the switch-on time t _on and the switch-off time t _off of the wastewater pump unit 2. It is not required for the proper operation or function of the wastewater pump unit 2. This is completely unaffected by the sensor 14.

The operating time T _on or the operating break time T _off is then evaluated in order to obtain at least additional information about the wastewater pump unit 2 and/or the wastewater pump system 1, see step Sd in Figure 9 .

The evaluation can be carried out in the evaluation unit 15. In the Figure 1 However, in the embodiment shown, the evaluation is carried out on a remote server 18 which is connected to the Internet 17 and to which the Evaluation unit 15 sends the current operating time T _on and/or the current operating break time T _off . The latter takes place here via a radio connection 16, for example via a mobile network, which forwards this data to the server 18 via the Internet. The server 18 can centrally monitor and manage the wastewater pump system 1, in particular a large number of wastewater pump systems 1. Technical errors and/or the need for maintenance can thus be immediately identified by specialist personnel and appropriate measures can be initiated.

It should be noted that the sensor 14 can also be integrated directly into the evaluation unit 15, so that a housing of the evaluation unit 15 is attached to the motor. If the evaluation unit 15 is then arranged under water, communication would not work, so that the evaluation unit 15 preferably establishes a connection to the Internet 17 or server 18 after the wastewater pump unit 2 has been switched off, i.e. after the container 3 has been pumped empty and the evaluation unit 15 is no longer under water, and makes the stored information available about the switch-on time t _on , the switch-off time t _o ff, the current operating time T _on and/or the current operating break time T _off .

Depending on the additional information required, the evaluation by the server 18 can be carried out in different ways.

For example, the additional information can be the volume of wastewater pumped by the wastewater pump unit 2. In this case, the current operating time T _on is multiplied by a nominal or average pumping power that the wastewater pump unit 2 has during operation. As a boundary condition for this, it must be taken into account that the wastewater pump unit 2 runs at a constant speed after being switched on. This can be a fixed speed or a speed specified by a frequency converter of the wastewater pump unit 2. The nominal or average pumping power can have been measured by the manufacturer for an identically constructed wastewater pump unit 2 and can therefore be available from the server 18. In addition, further data on the specific application in which the wastewater pump unit 2 is operated can be provided by the Server 18, such as the geodetic head or the system curve, in order to correctly determine the pumping capacity of the wastewater pump unit 2.

If the operating time T _on is, for example, 10 minutes, the pumped wastewater volume at a pumping capacity of 60 m ³ /h (1 m ³ /min) is 10 m ³ . If no new wastewater flows into the tank 3 during the pumping process, the pumped wastewater volume should correspond to the so-called switching volume, which corresponds to the tank volume between the maximum water level h _on and the minimum water level h _off . If it does not correspond to the switching volume, this indicates a faulty condition of the wastewater pumping system 1, as will be explained below.

bestimmt.In another embodiment, the additional information can be approximately the volume flow Q _out of the wastewater pump unit 2 that is pumped out of the container. It is calculated according to the equation $$Q_{\mathit{out}}=\frac{T_{\mathit{on}}+T_{\mathit{off}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

certainly.

bestimmt.In yet another embodiment, the additional information can be approximately the inflow Q _into the container 3. It is calculated according to the equation: $$Q_{\mathit{in}}=\frac{T_{\mathit{on}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

certainly.

In the two equations, Q _out is the volume flow of the sewage pump unit 2, T _{on is} the operating time, T _off is the operating break time, A is the cross-section (base area) of a cylindrical container 3, h _{on is} the switch-on level in container 3 at which the sewage pump unit 2 is switched on, and h _off is the switch-off level in container 3 at which the sewage pump unit 2 is switched off.

However, particularly preferred are embodiments in which the additional information relates to the state of the wastewater pump unit 2 or the wastewater pump system 1, in particular indicating whether a faulty state exists.

In one embodiment, the determined operating time T _on is compared with a reference operating time T _on,ref and the result of the comparison is used to determine the state of the wastewater pump unit 2 and/or the wastewater pump system 1. The reference operating time is either a standard operating time that an identical reference wastewater pump unit requires to pump the switching volume out of the container 3, or an earlier operating time of the wastewater pump unit 2 that was recorded, for example, during the initial operation after the installation of the wastewater pump system. The reference operating time T _on,ref is stored in a memory in the server 18 or in a database to which the server 18 has access. A comparison of the determined operating time T _on with the reference operating time T _on,ref is possible in Figure 6 visualized. A faulty state A in the form of a blockage of the sewage pump unit 2, a bearing or impeller damage of the sewage pump unit 2 or a blockage of the pressure line 9 connected to it is concluded if the operating time T _on is greater than or greater by a limit value t _lim than the reference operating time T _on,ref . In this case, the server 18 can generate a service message with an alarm and transmit it to a user who can immediately carry out or arrange for maintenance or repair.

As an alternative to comparing the operating time T _on with the reference operating time T _on,ref, an operating variable of the wastewater pump unit 2 can also be derived from the operating time T _on , such as a theoretically pumped volume, and this can be compared with a reference variable, e.g. the switching volume. If the operating variable exceeds the reference variable or exceeds it by a limit value, the faulty state mentioned is also assumed.

The limit value t _lim can, for example, be between 5% and 20% of the reference operating time T _on,ref or the reference value in order to take measurement inaccuracies into account.

According to another embodiment, a faulty state B in the form of a deposit such as a sediment accumulation in the container 3 can be concluded if the operating time T _on or the value derived therefrom is less than or less than the reference operating time T _on,ref or the reference value by a limit value t _lim . The comparison between operating time T _on and reference operating time T _on,ref is illustrated by Figure 7 .

In one embodiment, the operating time T _on or the operating break time T _off are calculated for each operation of the waste water pump unit 2 and a trend is determined from the calculated operating times T _on or operating break times T _off . Figure 8 illustrates the case where the operating time T _on is longer than before each time the sewage pump unit 2 is operated, so that a trend ΔT _on /Δt greater than zero is present. The trend can be compared with a limit value in order to determine whether the gradual increase in the operating time T _on is due to expected wear or is caused by a faulty condition. A faulty condition in the form of a blockage in the sewage pump unit 2, a bearing or impeller defect in the sewage pump unit 2 or a blockage in the pressure line 9 connected to it is concluded if the trend ΔT _on /Δt of the operating times T _on is positive and exceeds a limit value in terms of amount. Alternatively or cumulatively, a faulty condition in the form of a deposit, in particular an accumulation of sediment in the container 3, is concluded if the trend of the operating time T _on is negative and falls below a limit value in terms of amount.

Figures 2 and 3 show to Figure 1 alternative design variants. They differ from the variant in Figure 1 only in the local arrangement of the sensor 14. Thus, the sensor in the design variant according to Figure 2 on the pressure line 9. Since this is mechanically connected to the sewage pump unit 2, its vibrations are also transmitted to the pressure line 9. The sensor 14 is therefore also a vibration sensor. The advantage of this variant is that the sensor is positioned dry and can therefore be easily retrofitted. In the Figure 3 In the embodiment shown, the sensor 14 is an inductive current sensor with a toroidal core through which the supply cable 12 of the sewage pump unit 2 is routed. The physical quantity detected by the sewage pump unit 2 is therefore its current consumption. When the sewage pump unit 2 is switched on, the signal from the sensor 14 indicates a current flow. After the sewage pump unit 2 is switched off, the sensor signal is zero. Thus, a rising edge in the sensor signal or an exceedance of a signal limit value indicates the switch-on time t _on and a falling edge in the sensor signal or an undershoot of a signal limit value indicates the switch-off time t _off . The evaluation unit 15 checks the sensor signal for the occurrence of one of the above-mentioned events (edge, exceedance/undershoot of limit value) in order to determine the switch-on time t _on and the switch-off time t _off . From this, it then calculates the operating time T _on and/or the operating break time T _off as before and forwards these to the server 18, which then carries out an evaluation as described above.

In other versions, which are Figures 4 and 5 are shown, the wastewater pump system 1 comprises a first wastewater pump unit 2a and at least one second wastewater pump unit 2b. The method according to the invention is also carried out on the second wastewater pump unit 2b, ie its operating time T _on and/or operating break time T _off is calculated and at least one additional piece of information about the second wastewater pump unit 2b and/or the wastewater pump system 1 is determined therefrom, as explained above with reference to the first wastewater pump unit 2a or the case of a single wastewater pump unit 2. Both wastewater pump units 2a, 2b each have a sensor 14 which is connected via a corresponding signal line 19 to an evaluation unit 15, 15a, 15b which, as described above, evaluates the respective sensor signal.

In one embodiment, however, the respective operating time T _on is not compared with a standard operating time T _on,ref or a previous operating time of the respective wastewater pump unit 2a, 2b, but rather the Operating time T _on of the first wastewater pump unit 2a is compared with the operating time T _on of the second wastewater pump unit 2b. In other words, the reference operating time T _on,ref here is the calculated operating time T _on of the second wastewater pump unit 2b.

Figure 4 illustrates a wastewater pump system 1 in which the second wastewater pump unit 2b is arranged together with the first wastewater pump unit 2a in the container 3 and is operated alternately with it. Both wastewater pump units 2a are switched on and off by the same control 10. A faulty state in the form of a blockage of the first wastewater pump unit 2a, a bearing or impeller damage of the first wastewater pump unit 2a or a blockage of the sewage line 9 connected to it is concluded if the operating time T _on of the first wastewater pump unit 2a is greater than or greater by a limit value than the operating time T _on of the second wastewater pump unit 2b. Conversely, a faulty state in the form of a blockage of the second wastewater pump unit 2b, a bearing or impeller damage of the second wastewater pump unit 2a or a blockage of the sewage line 9 connected to it can be concluded if the operating time T _on of the second wastewater pump unit 2b is greater than or greater by a limit value than the operating time T _on of the first wastewater pump unit 2a. The comparison is also carried out here by the server 18, which can also send a service message to a user if the faulty state has been detected.

Figure 5 illustrates a wastewater pump system 1 in which the first wastewater pump unit 2a is arranged in a first container 3a and the second wastewater pump unit 2b is arranged in a second container 3b. Each wastewater pump unit 2a, 2b is switched on and off by its own control 10, depending on the water level 13 in the respective container 3a, 3b, which is transmitted by a level sensor 5 via a measuring line 11a, 11b to the respective control 10. The second container 3b is connected to the first container 3a via a wastewater line 9a, 8b. The wastewater line 9a, 8b consists of a pressure line 9a, which is connected to the first wastewater pump unit 2a and transports the waste water pumped by it, and an adjoining inlet line 8b, via which the waste water 4 is fed into the second container 3b. This means that the first waste water pump unit 2a, during operation, pumps waste water 4 into the second container 3b via the waste water line 9a, 8b. There is no further inlet into the second container 3b.

The first and second containers 3a, 3b are separated from each other by a longer distance, for example several hundred meters, in order to transport the waste water 4 to a water treatment plant. In practice, several such containers 3a, 3b connected in series with waste water pump units 2a, 2b are required for this purpose.

Each wastewater pump unit 2a, 2b is also assigned a corresponding sensor 14, which is a vibration sensor here, for example. Each of the sensors 14 transmits its sensor signal via a signal line 19 to a corresponding evaluation unit 15a, 15b, which, as previously described, evaluates the respective sensor signal for the occurrence of an event indicating the switch-on time t _on and the switch-off time t _off and then calculates the operating time T _on and/or the operating break time T _off of the respective wastewater pump unit 2a, 2b. Each evaluation unit 15a, 15b then transmits this to the server 18 for further evaluation or to obtain additional information about the wastewater pump system 1.

Due to the lack of further inflow, in the case shown it can be concluded that the wastewater pump system 1 is in a faulty state in the form of a leak in the wastewater line 9a, 8b if the sum of the operating times T _on of the first wastewater pump unit 2a in a certain observation period is greater than or greater by a limit value than the sum of the operating times T _on of the second wastewater pump unit 2a in the observation period, which in this case forms the reference operating time T _on,ref .

Additionally or alternatively, a faulty condition of the sewage pump system 1 in the form of an impermissible inflow of water into the Wastewater line 9a, 8b is closed if the sum of the operating times T _on of the first wastewater pump unit 2a in a specific observation period is less than or less than a limit value than the sum of the reference operating times T _on,ref in the observation period. In this case, water enters the wastewater pump system 1 which is not intended to be pumped by it.

In another embodiment, the operating break time T _off of the second wastewater pump unit 2b, i.e. the period between two operations of the second wastewater pump unit 2b, is repeatedly determined and compared with a reference break time T _off,ref . A faulty state in the form of an abnormal inflow of water into the wastewater pump system 2 is concluded if the operating break time T _off is repeatedly less than or less than the reference break time T _off,ref by a limit value. The reference break time T _off,ref can in this case be the average operating break time T _off of the second wastewater pump unit 2b.

As already noted, the method according to the invention can be used in a variety of different wastewater pumping systems.

It should be noted that the above description is given merely by way of example for the purpose of illustration and in no way limits the scope of the invention. Features of the invention which are specified as "can", "exemplary", "preferred", "optional", "ideal", "advantageous", "if necessary", "suitable" or the like are to be considered purely optional and also do not limit the scope of protection, which is determined exclusively by the claims. To the extent that elements, components, process steps, values or information are mentioned in the above description which have known, obvious or foreseeable equivalents, these equivalents are also included in the invention. Likewise, the invention includes any changes, variations or modifications of embodiments which involve the exchange, addition, change or omission of elements, components, process steps, values or information, as long as the basic idea of the invention is retained, regardless of whether the change, variation or modification results in an improvement or deterioration of an embodiment.

Although the above description of the invention mentions a large number of physical, non-physical or method-related features in relation to one or more specific embodiment(s), these features can also be used in isolation from the specific embodiment, at least as long as they do not require the mandatory presence of further features. Conversely, these features mentioned in relation to one or more specific embodiment(s) can be combined with one another as desired and with further disclosed or undisclosed features of embodiments shown or not shown, at least as long as the features do not exclude one another or lead to technical incompatibilities.

List of reference symbols

• 1 sewage pumping system
• 2 sewage pump unit
• 2a first sewage pump unit
• 2b second sewage pump unit
• 3 Container
• 3a first container
• 3b second container
• 4 Wastewater
• 5 Water level sensor
• 6 Suction side
• 7 Print page
• 8 Inlet line
• 8a first inlet line
• 8b second inlet line
• 9 Pressure pipe, sewage pipe
• 9a first pressure line, sewage line
• 9b second pressure line, sewage line
• 10 Control unit
• 11 Measuring line
• 11a first measuring line
• 11b second measuring line
• 12 Supply line
• 13 Water level
• 14 Sensor
• 15 Evaluation unit
• 15a first evaluation unit
• 15b second evaluation unit
• 16 Radio transmission
• 17 Internet
• 18 servers
• 19 Signal line

Claims (21)

Method for obtaining information, in particular for condition monitoring, in a wastewater pump unit (2) of a wastewater pump system (1) and/or in a wastewater pump system (1) comprising at least one wastewater pump unit (2, 2a), wherein the wastewater pump unit (2, 2a) pumps wastewater (4) out of a container (3) for collecting the wastewater (4) during operation, characterized in that a) with the aid of a separate sensor (14), an externally measurable physical quantity of the sewage pump unit (2, 2a) and/or the sewage pump system (1) is detected, b) the switch-on time (t _on ) and the switch-off time (t _off ) of the sewage pump unit (2, 2a) are determined from the measured value, c) an operating time (T _on ) or operating break time (T _off ) is calculated from the switch-on time (t _on ) and the switch-off time (t _off ), the sensor (14) being used to determine the switch-on time (t _on ) and the switch-off time (t _off ) of the sewage pump unit (2, 2a), and d) the operating time (T _on ) or the operating break time (T _off ) is evaluated in order to obtain at least additional information about the waste water pump unit (2, 2a) and/or the waste water pump system (1). Method according to claim 1, characterized in that in step d) the operating time (T _on ), or an operating variable determined therefrom, is compared with a reference operating time (T _on,ref ) or a reference variable, the result of the comparison being used to determine the state forming the additional information, in particular an error state of the sewage pump unit (2, 2a) and/or the sewage pump system (1) is closed. Method according to claim 2, characterized in that the reference operating time (T _on,ref ) is a previous operating time of the waste water pump unit (2, 2a) or that the reference variable is a variable determined from a previous operating time of the waste water pump unit (2, 2a). Method according to one of claims 2 or 3, characterized in that a faulty state in the form of a blockage of the waste water pump unit (2, 2a), a bearing or impeller damage of the waste water pump unit (2, 2a) or a blockage of a pressure line (9) connected thereto is concluded if the operating time (T _on ) or the operating variable derived therefrom is greater than or greater by a limit value (t _lim ) than the reference operating time (T _on,ref ) or the reference variable. Method according to one of claims 2 to 4, characterized in that a faulty state in the form of a deposit, in particular a sediment accumulation in the container (3) is concluded if the operating time T _on or the variable derived therefrom is less than or smaller by a limit value (t _lim ) than the reference operating time (T _on,ref ) or the reference variable. Method according to one of claims 2 to 5, characterized in that the operating time (T _on ) or the operating break time (T _off ) is calculated repeatedly according to steps a) to c) during each operation of the waste water pump unit (2, 2a) and a trend forming the operating variable is determined from the calculated operating times (T _on ) or operating break times (T _off ), and that the reference variable forms a limit value for the trend. Method according to claim 6, characterized in that a faulty condition in the form of a blockage of the Wastewater pump unit (2, 2a), a bearing or impeller damage of the wastewater pump unit (2, 2a) or a blockage of a pressure line (9) connected to it is closed if the trend of the operating times (T _on ) is positive and exceeds a limit value. Method according to claim 6 or 7, characterized in that a faulty state in the form of a deposit, in particular an accumulation of sediment in the container (3) is concluded if the trend of the operating time (T _on ) is negative and falls below a limit value. Method according to claim 2, characterized in that the waste water pump system (1) comprises at least one second waste water pump unit (2b), in which steps a) to c) are carried out in order to calculate an operating time (T _on ) of the second waste water pump unit (2b), and in that the reference operating time (T _on,ref ) is the calculated operating time (T _on ) of this second waste water pump unit (2b) or the reference variable is an operating variable determined from the calculated operating time (T _on ) of this second waste water pump unit (2b). Method according to claim 9, characterized in that the second waste water pump unit (2b) is arranged in a second container (3b) or is connected thereto in order to pump waste water from the second container (3b), and the first waste water pump unit (2a) pumps waste water (4) from the first container (3a) into the second container (3b) via a waste water line (9a, 8b) during operation, and that the sum of the operating times (T _on ) of the first waste water pump unit (2a) in a certain period of observation is formed and used as an operating variable, and the sum of the operating times (T _on ) of the second waste water pump unit (2b) in the period of observation is formed and used as a reference variable, and that a faulty state of the waste water pump system (1) in the form of a leak in the Wastewater pipe (9a, 8b) is closed if the operating size is greater than or greater than the reference size by a limit value. Method according to claim 9 or 10, characterized in that the second wastewater pump unit (2b) is arranged in a second container (3b) or is connected thereto in order to pump wastewater from the second container (3b), and the first wastewater pump unit (2a) pumps wastewater (4) from the first container (3a) into the second container (3b) via a wastewater line (9a, 8b) during operation, and that the sum of the operating times (T _on ) of the first wastewater pump unit (2a) in a specific observation period is formed and used as an operating variable, and the sum of the operating times (T _on ) of the second wastewater pump unit (2b) in the observation period is formed and used as a reference variable, and that a faulty state of the wastewater pump system (1) in the form of an impermissible inflow of water into the wastewater line (9a, 8b) is concluded if the operating variable is smaller than or smaller by a limit value than the reference variable. Method according to claim 9, characterized in that the second sewage pump unit (2b) is arranged together with the first sewage pump unit (2a) in the container (3) or is connected thereto and is operated alternately with the first sewage pump unit (2a), wherein a faulty state in the form of a blockage, a bearing or impeller damage of the first sewage pump unit (2a) or a blockage of a sewage line (9) connected thereto is concluded if the operating time (T _on ) of the first sewage pump unit (2a) or the operating variable derived therefrom is greater than or greater by a limit value than the reference operating time (T _on,ref ) or the reference variable. Method according to one of claims 2 to 5 or 9 to 12, characterized in that the operating variable is a variable resulting from the operating time calculated wastewater volume and the reference value is a corresponding reference wastewater volume. Method according to one of the preceding claims, characterized in that steps a) to c) are repeated and the respectively calculated operating break duration (T _off ) in step d) or an operating break size determined therefrom is compared with a reference break duration (T _off,ref ) or a reference break size and a faulty state in the form of an impermissible inflow of water into the wastewater pump system (2) is concluded if the operating break duration (T _off ) is repeatedly less than or less than the reference break duration (T _off,ref ) by a limit value. Method according to one of the preceding claims, characterized in that in step d) the wastewater volume pumped by the wastewater pumping unit (2, 2a) is determined from the operating time (T _on ), which forms the additional information. Method according to one of the preceding claims, characterized in that the operating time (T _on ) is determined from the switch-on time (t _on ) and the switch-off time (t _off ) that follows thereafter, and the switch-on _{time (t on )} of the wastewater pump unit (2, 2a) is determined from the detected value after an operating break following the switch-off time (t off ), and the operating break time (T _off ) is calculated from the last switch-off time (t _off ) and the switch-on time (t _on ) that follows thereafter, wherein in step d) the operating time (T _on ) and the operating break time (T _off ) are approximately - the volume flow (Q _out ) of the sewage pump unit (2, 2a) as additional information according to the equation: $$Q_{\mathit{out}}=\frac{T_{\mathit{on}}+T_{\mathit{off}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

is determined, and/or - the inflow (Q _in ) into the container (3) as additional information according to the equation: $$Q_{\mathit{in}}=\frac{T_{\mathit{on}}}{T_{\mathit{on}}\cdot T_{\mathit{off}}}\cdot A\left(H_{\mathit{off}}-H_{\mathit{on}}\right)$$

is determined, whereby Q _out is the volume flow of the sewage pump unit (2, 2a), T _on the operating time, T _off is the operating break time, A is the cross-section of a cylindrical container (3) h _on a switch-on level in the container (3) at which the sewage pump unit (2, 2a) switches on and h _off is a switch-off level in the container (3) at which the sewage pump unit (2, 2a) switches off. Method according to one of the preceding claims, characterized in that the sensor (14) transmits its sensor signal to an evaluation unit (15), which evaluates the sensor signal, calculates the operating time (T _on ) and/or operating break time (T _off ) and then transmits it to a remote server (18), in particular one connected to the Internet (17), on which step d) is carried out. Method according to one of the preceding claims, characterized in that a service message is generated and transmitted to a user when a faulty condition has been detected. Method according to one of the preceding claims, characterized in that the sensor (14) is attached externally to the wastewater pump unit (2, 2a) or to a part of the wastewater pump system (1) operatively connected thereto, in particular to a drive motor, a pump unit, a gear, a lantern, a rod, a pressure line (9) or a supply cable (12) of the wastewater pump unit (2, 2a). Method according to one of the preceding claims, characterized in that the sensor (14) is a vibration sensor, a current sensor or a magnetic field sensor. Method according to one of the preceding claims, characterized in that the switch-on time (t _on ) and the switch-off time (t _off ) are determined by a signal supplied by the sensor (14) exceeding or falling below a limit value, having a rising or falling edge or having a sign change.

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