Centrifugal pump and method for status detection of a centrifugal pump

Description

[0001] The present invention relates to a centrifugal pump and a method for detecting the condition of a centrifugal pump.

[0002] Centrifugal pumps are used in a wide variety of applications to pump liquids. Especially with process water or wastewater, the fluid being pumped often contains impurities that can potentially lead to blockages or undesirable impairment of the pump's performance. Typically, foreign matter becomes wrapped around the impeller shaft or blades, reducing the pump's efficiency. In extreme cases, the wrapping of foreign material around the impeller's axis of rotation can cause a complete blockage or similar problem.

[0003] From the prior art, e.g. from WO 2008 / 119931 A2, a method for detecting such an undesired condition is known in which the current consumption of the pump is monitored and, in the case of deviations from a normal value, a blockage is inferred.

[0004] EP 2 538 085 A2 describes a pump arrangement with a pumping device in which a diagnostic unit is provided for determining the operating status of the pumping device.

[0005] JP 2010101192 A discloses a device for predicting the amount of erosion in a turbine impeller due to cavitation by capturing an image of a section in which cavitation occurs.

[0006] The aim of the present invention is to provide the simplest and most reliable condition detection possible for centrifugal pumps, so that even incipient blockage conditions can be detected early and appropriate countermeasures can be initiated.

[0007] This can be achieved with a pump arrangement having all the features of claim 1 or by means of a method that performs all the method steps according to claim 10.

[0008] Further advantageous embodiments of the invention or further advantageous specifications of the method can be found in the respective dependent claims.

[0009] According to claim 1, the pump arrangement for conveying a liquid, in particular for conveying wastewater or process water, comprises a pump housing with a suction port for drawing in the liquid to be conveyed, and an impeller rotatably arranged in the pump housing for conveying the liquid. At least one sensor, in particular a 3D sensor, for detecting the surface of the impeller is provided, wherein this sensor is arranged on and / or in the pump housing. By providing a sensor whose detection range is directed towards the impeller, a specific section of the impeller can be detected continuously or intermittently. Using an evaluation unit that analyzes the sensor's acquired data, it is then possible to determine whether a fault condition exists, such as an impending blockage or advanced plaque formation.

[0010] The optional 3D functionality allows the sensor to obtain information about objects adhering to or in front of the wheel, enabling a reliable assessment of the presence of unwanted objects.

[0011] Since it is not uncommon, especially when pumping process water or even wastewater, for small or large solid objects to be present in the fluid being pumped, the mere fact that such an object is caught once in front of the impeller will not usually lead to a malfunction. Rather, a characteristic of clogging is that a solid object covers the same or a similar area of ​​the impeller surface for several revolutions and is not carried away with the pumped fluid.

[0012] According to a further development of the invention, it can be provided that the sensor is designed to determine a distance to the impeller, preferably using Time-of-Flight technology (also: ToF technology).

[0013] Time-of-flight (ToF) technology is essentially based on measuring the transit time of an emitted signal. This allows for a fairly accurate calculation of the distance between an object and the signal origin. This method is particularly advantageous in this application because ToF sensors are especially robust and suitable for installation in centrifugal pumps, where they can withstand the harsh conditions.

[0014] As briefly explained above, determining the distance between the sensor and the impeller or an object adhering to it is an effective way to detect the presence of objects being pulled around the rotational axis of the impeller.

[0015] As an advantageous alternative, the sensor can be designed to measure a distance to the impeller using the phase difference method.

[0016] Another advantageous alternative is the Frequency-modulated continuous-wave technology (FMCW or Frequency-modulated continuous wave).

[0017] According to an optional modification of the present invention, the sensor may be an optical sensor, an optical 2D sensor, an optical 3D sensor, a 2D ultrasonic sensor, a 3D ultrasonic sensor, a MIMO radar sensor (Multiple-Input Multiple-Output radar sensor), a 2D laser distance sensor and / or a 3D laser distance sensor, preferably based on the triangulation principle.

[0018] According to a preferred embodiment of the invention, the impeller can be provided on its surface with a characteristic pattern that can be detected by the sensor at a certain rotational position of the impeller; preferably, the pattern is a 2D pattern or a 3D pattern.

[0019] Applying a pattern to the impeller makes it easier for the sensor to optically detect a specific area of ​​the impeller and simplifies the evaluation of the images generated by the sensor. This allows a characteristic pattern, tailored to the specific sensor type, to be recognized much more easily, even if the images were not taken under optimal conditions or are partially obscured by particles present in the fluid being pumped. The fluid being pumped will typically contain absorbing particles that degrade image quality. Furthermore, even with illumination of the impeller area, a cloudy or dirty fluid being pumped can significantly reduce image quality.In this case, it is advantageous to use the characteristic pattern, as this facilitates a significantly better conclusion about the presence of blockages or the like, even under non-optimal conditions.

[0020] Therefore, it may be possible to include a light source in and / or on the pump housing to illuminate the sensor's detection area. This is particularly helpful for optical sensors, which require sufficient illumination to capture an optical image.

[0021] According to an optional modification of the invention, it can be provided that the light source is designed to emit intermittent light pulses, wherein the intermittently emitted light pulses are synchronized with a pump speed.

[0022] The light pulse can thus be generated only when the area of ​​interest on the impeller is within the sensor's detection range, and deactivated again once it leaves this range. The illumination of the detection area is preferably coupled to the pump speed, eliminating the need for complex control systems.

[0023] According to the invention, a micropump is provided for rinsing a sensor surface in order to actively remove residues that accumulate in front of the sensor surface. This micropump is a component located inside the pump housing 10, which, for example, directs a portion of the fluid being pumped onto the sensor surface in a targeted manner, preventing unwanted deposits from accumulating there. Alternatively, the sensor surface is not continuously irrigated but only when needed. The micropump is thus ultimately designed to spray the sensor surface clean, 15 so that no disruptive residues can accumulate there or existing residues can be removed. The micropump can also be integrated into the sensor itself.

[0024] Another alternative or additional method for keeping the sensor surface clean is provided according to the invention by means of an ultrasonic microactuator, which is designed to set an outer housing or a sensor surface of the sensor into an ultrasonic vibration motion. This causes any dirt layer that accumulates on it to be broken up or prevents a dirt layer from forming in the first place. This also prevents the accumulation of unwanted residues on the surface of the sensor.

[0025] According to the invention, the pump can further be provided with an additional feed port on the suction side for supplying clean water in order to at least temporarily reduce any turbidity of the fluid being pumped in the impeller area. Often, the turbidity of the liquid flowing through the pump impairs the sensor's performance, as the resulting images may be unusable or only partially usable. To ensure that condition detection functions reliably even with a very dirty liquid, the invention provides, in addition to the suction port for drawing in the liquid to be pumped, a feed port on the suction side of the pump. This feed port allows a clear liquid, such as clean water, to be introduced into the pump as needed, for example, during or shortly before a sensor measurement.This results in the turbidity of the liquid being temporarily reduced, at least during the recording made by the sensor, so that the recordings made during this time are more meaningful.

[0026] According to a further development of the invention, the feed nozzle can be designed to supply a clear liquid depending on the pump speed. This allows the clear liquid to reduce turbidity around the sensor area when an image is captured, thus enabling better images to be obtained.

[0027] It is advantageous if the feed nozzle is also located in the pump housing, since then the distance to the receiving area is small and mixing of a supplied clear liquid has not yet taken place to the extent that would have been the case with a more distant arrangement of the feed nozzle.

[0028] According to a further development of the invention, it can be provided that the pump arrangement has a control unit which is connected to the sensor and is designed to evaluate image data obtained from the sensor and, based on this, to conclude that there is a fault, in particular a blockage, a braiding, a cavitation, mechanical damage and / or vibrations.

[0029] This happens, for example, when the recording detects that it is not the impeller that is visible, but rather an object positioned between the impeller and the sensor.

[0030] Preferably, the evaluation of an image captured by the sensor is carried out using artificial intelligence, preferably based on deep learning. This improves the reliability of detecting an impending or even existing fault condition, such as braiding or blockage.

[0031] The invention also relates to a method for detecting a fault in a pump arrangement, in particular a centrifugal pump arrangement, according to one of the variants described above, wherein in the method the sensor generates recordings of the impeller, and the data generated by the sensor or recordings of the impeller are evaluated by a control unit in order to conclude about the fault, in particular a blockage, a braiding, a cavitation, mechanical damage and / or vibrations.

[0032] The advantage of this new approach is that the components for automated image processing are inexpensive and very powerful, and it is no longer necessary – as is common in the prior art – to build a separate logic that monitors the pump's power consumption for deviations.

[0033] One of the claimed options involves adding clean water to the pump's suction side shortly before impeller images are taken, in order to reduce any potential turbidity of the liquid surrounding the impeller at the time of recording. Preferably, the sensor images may depict a specific area of ​​the impeller with a characteristic pattern, thus facilitating the assessment of whether a blockage or plaiting is present, as the pattern would otherwise be difficult or impossible to discern. For this purpose, a special 2D or 3D pattern can be applied to the impeller, making the images easier to evaluate.

[0034] Furthermore, the method may provide that the creation of the recordings is synchronized with the rotational speed of the impeller in order to continuously capture a specific section or several specific sections of the impeller with the sensor, preferably in an intermittent manner.

[0035] Furthermore, the area of ​​the wheel to be recorded can be illuminated with a light source before recording, so that the recordings allow for better and easier evaluation, especially when the sensor is implemented as an optical sensor.

[0036] Furthermore, according to the invention, it can be provided that activities of an operating person of the pump, such as switching the pump on or off and / or an error acknowledgment, are monitored using the sensor in order to obtain a more reliable actual state of the pump.

[0037] This is particularly important for reducing the overall probability of errors, where often faulty sensors fail to accurately reflect the actual state. The method according to the invention further reduces this probability.

[0038] Further advantages, details, and features will become apparent from the following description of the figures. They show the Fig. 1 is a sectional view of a pump arrangement according to the invention with the sensor, Fig. 2 is a sectional view of another pump according to the invention with the sensor, and Fig. 3 is a sectional view of another pump according to the invention with the sensor.

[0039] The Fig. 1 Figure 1 shows a vertically positioned pump arrangement 1 with a pump housing 3 having a flow chamber 2 and an impeller 4 arranged therein, which, when rotating about its axis of rotation A, conveys a liquid from its suction port 5 to its pressure port 6.

[0040] Furthermore, a sensor 7 is provided in and / or on the pump housing 3, which is directed towards a surface of the impeller 4. This allows the sensor 7 to detect whether an object 8 is present in front of the impeller surface that reduces the performance of the pump 1. Typically, this can detect an impending blockage of the pump 1 or indicate the formation of a braid.

[0041] A braiding occurs when a solid body 8 adheres to the impeller 4 and is not discharged to the pressure side, even during continuous rotation. Due to the constant dragging along the fluid being pumped, other free-floating elements adhere to it, causing the braid to grow and increasingly impairing the performance of pump 1. This can sometimes lead to a complete blockage of pump 1.

[0042] To detect such a condition as early as possible, the recordings or the information captured by sensor 7 are sent to a control unit 9 via a cable 10 or wirelessly, so that appropriate evaluation can take place there. This is advantageously done with the help of artificial intelligence, whereby deep learning technology can also be used.

[0043] In this process, the expected uptake of the impeller surface is compared with the actual uptake, from which it can be deduced whether a braiding occurs or even a blockage is present.

[0044] To achieve better alignment, a pattern 11 has been applied to the surface of the impeller 4 in the illustrated embodiment, which is particularly easy for the sensor 7 to detect. When the sensor 7 detects the pattern 11, an object 8 located in front of it can be detected particularly well, thus improving the reliability of fault condition detection.

[0045] Reference numeral 12 symbolically represents a communication interface which, in an optional modification of the invention, can be used to further transmit the results of the evaluations.

[0046] To ensure that condition detection functions flawlessly even with a very dirty liquid, a claimed option is provided that, in addition to the suction port 5 for drawing in the liquid to be pumped, a feed port 13 is located on the suction side of the pump arrangement 1, through which a clear liquid, e.g. clear water, is introduced into the pump 1 as needed, e.g. during or shortly before a reading by the sensor 7.

[0047] The Fig. 2 Figure 1 shows a further embodiment of the pump arrangement 1, in which the sensor 7 is arranged in a recessed area 14 from the flow chamber 2. Thus, the sensor 7 is in contact with the pumped medium, but better protected against abrasive wear, mechanical shocks from solids contained in the medium, as well as contamination and sedimentation. The recessed area is described in the Fig. 2shown as a bulge in the pump housing. Alternatively, the recessed area 14 can be created by mechanical machining, in particular by machining, of the inside of the pump housing 3. Fig. 3 Figure 1 shows a vertically mounted pump arrangement 1, in which the sensor 7 is arranged in a cover 15 to close a so-called cleaning hole 16. This eliminates the need for a bore in the pump housing 3.

[0048] It is understood that in the lid 15 there is a recessed area, similar to the one in the Fig. 2 Area 14 shown may be provided for. Furthermore, it is possible that the areas shown in the Fig. 1 and 2 The pump arrangements shown 1 with a cover 15 according to the Fig. 3 It may be equipped.

[0049] To illuminate the detection area of ​​the sensor 7, a light source not shown in the figures can be provided in and / or on the pump housing 3 or on the sensor 7 itself.

[0050] The sensor 7, the light source and / or the micropump can also be placed at other suitable locations in or on the pump housing 3, for example near the suction port 5 and / or near the pressure port 6. Figures 1 to 3 Each figure shows a single-stage pump arrangement with an impeller 4 that ejects in a radial direction. The invention can, for example, also be provided in a pump arrangement 1 that is multi-stage and / or equipped with an impeller 4 that ejects in an axial or semi-axial direction.

[0051] The one that goes to the Fig. 1 The described feed nozzle 13 can also be used in the other embodiments of pump arrangements 1.

Claims

1. Pump arrangement (1) for conveying a liquid, in particular for conveying waste water or process water, comprising: a pump housing (3) comprising an intake connection (5) for drawing in the liquid being conveyed, an impeller (4) rotatably arranged about a centre of rotation (A) in the pump housing (3) for conveying the liquid, and at least one sensor (7), in particular a 2D or a 3D sensor, for capturing the surface of the impeller (4), the at least one sensor (7) being arranged on and / or in the pump housing (3), characterized in that the pump arrangement (1) comprises a micro-pump for rinsing a sensor surface of the sensor (7), so that residues accumulating in front of the sensor surface are actively removed, and / or in that the pump arrangement (1) comprises an ultrasound micro-actuator in order to start an ultrasound shaking motion in an outside housing or a sensor surface of the 3D sensor (7), so that a layer of dirt which is deposited thereupon is broken up or a layer of dirt is prevented from forming in the first place, and / or in that the pump arrangement (1) comprises a further supply connection (13) on the suction side of the pump (1) for supplying clean water, so that any possible murkiness in the fluid being conveyed is reduced, at least briefly, in the region of the impeller (4).

2. Pump arrangement (1) according to Claim 1, wherein the sensor (7) is designed to determine a distance from the impeller (4), preferably with the help of the time-of-flight technology.

3. Pump arrangement (1) according to Claim 1, wherein the sensor (7) is designed to determine a distance from the impeller (4) with the help of the phase-difference method.

4. Pump arrangement (1) according to Claim 1, wherein the sensor (7) is designed to determine a distance from the impeller (4) with the help of frequency-modulated continuous wave technology.

5. Pump arrangement (1) according to one of the preceding claims, wherein the sensor (7) is an optical sensor, an optical 2D sensor, an optical 3D sensor, a 2D ultrasound sensor, a 3D ultrasound sensor, a MIMO (multiple-input multiple-output) radar sensor, a 2D laser distance sensor and / or a 3D laser distance sensor, preferably based on the triangulation principle.

6. Pump arrangement (1) according to one of the preceding claims, wherein the impeller (4) is provided with a characteristic pattern (11) on its surface, which can be detected by the sensor (7) in a particular rotational position of the impeller (4); the pattern (11) in this case is preferably a 2D pattern or a 3D pattern.

7. Pump arrangement (1) according to one of the preceding claims, wherein a lighting means is provided in addition in and / or on the pump housing (3) or on the sensor (7) itself, in order to illuminate a detection range of the sensor (7).

8. Pump arrangement (1) according to Claim 7, wherein the lighting means is designed to emit intermittent light impulses, wherein the intermittently emitted light impulses are synchronized with a pump speed.

9. Pump arrangement (1) according to one of the preceding claims, in addition comprising a control unit (9) which is connected to the sensor (7) and is designed to analyse data received from the sensor (7) and to infer from this that there is a fault, in particular a blockage, plaiting, cavitation, mechanical damage and / or vibrations.

10. Method for detecting a fault in a pump arrangement (1) according to one of the preceding claims, wherein in the method: the sensor (7), in particular a 2D or a 3D sensor produces images of the impeller (4), and the data on the impeller (4) produced by the sensor (7) are analysed by a control unit (9), in order to infer a fault, in particular a blockage, plaiting, cavitation, mechanical damage and / or vibrations, characterized in that the sensor surface of the sensor (7) is rinsed, so that residues accumulating in front of the sensor surface are actively removed, and / or in that an ultrasound shaking motion is started in an outside housing or a sensor surface of the 3D sensor (7), so that a layer of dirt which is deposited thereupon is broken up or a layer of dirt is prevented from forming in the first place, and / or in that just before the images of the impeller (4) are captured, clean water is added on the suction side of the pump arrangement (1), in order to reduce any murkiness in the liquid present in the vicinity of the impeller (4) for the time the images are taken.

11. Method according to Claim 10, wherein the images taken by the sensor (7) reproduce a particular region of the impeller (4) which is provided with a characteristic pattern (11), so that the assessment of the presence of a blockage or plaiting is easier to carry out, since the pattern (11) cannot be identified in such a case, or only with some difficulty.

12. Method according to either of Claims 10 and 11, wherein the capture of the images is synchronized with the speed of the impeller (4), so that a particular portion, or multiple particular portions, of the impeller (4) can be continuously captured using the sensor (7) preferably in an intermittent manner.

13. Method according to one of the preceding Claims 10 to 12, wherein activities of a staff member operating the pump arrangement (1), such as the switching-on or off of the pump arrangement (1) and / or an error acknowledgement, are monitored with the help of the sensor (7), in order to obtain a more reliable current state.