WO2025078240A1 - Machine having an integrated submersible motor, in particular a submersible-motor stirrer or submersible-motor pump - Google Patents

Abstract

The invention relates to a machine having an integrated submersible motor, in particular a submersible-motor stirrer or a submersible-motor pump, having a housing, a plurality of integrated sensors and a sensor module installed inside the housing, wherein the sensor module has plurality of measured-value inputs for receiving any measurement signals of the sensors, and comprises a microcontroller that is configured to digitise the received measured values of the connected sensors and to transmit them to a remote evaluation unit via a common digital transmission path.

Description

Machine with integrated submersible motor, in particular submersible mixer or submersible pump

The invention relates to a machine with an integrated submersible motor, in particular a submersible mixer or a submersible pump, with a housing and several integrated sensors.

A submersible motor pump is a pump with a motor whose hydraulic components, such as the pump housing, impeller, and guide vane, as well as its motor, are submerged in the pumped medium. A submersible mixer is a mixer with open, axial propeller hydraulics and a submersible motor driving the propeller. Submersible pumps and mixers are typically installed in hard-to-reach locations, making remote monitoring desirable.

The increasing demands for machine safety and monitoring capabilities, as well as the growing demand for digital products, are necessitating more extensive and complex sensor installations within such machines. The use of informative yet affordable sensors, the centralization of information analysis, and data transmission via cost-effective electrical cables are market-driven objectives. Previously, the sensors installed in the machine were connected to an external control unit via separate data lines, which made installation and cabling particularly complex.

The aim of the invention was therefore to find an improved solution concept that reduces the installation effort, but at the same time can meet the higher requirements for digitalization and monitoring functionality.

This object is achieved by a machine according to the features of claim 1. Advantageous embodiments of the machine are the subject of the dependent claims.

According to the invention, it is proposed to install a sensor module within the machine, which is provided with several connections as measured value inputs. The connections serve as measured value inputs for several sensors installed in the machine. The sensor module is further equipped with a microcontroller, which is configured to process, in particular to digitize, at least some of the incoming measured values from the connected sensors. The sensor module further comprises a digital communication interface, which can be connected to an external evaluation unit. The microcontroller is configured to transmit the processed, in particular digitized, measured values to the remote evaluation unit via the digital transmission path.

In other words, the sensor module acts as a type of gateway that bundles, processes, and, in particular, digitizes various measured values provided by different sensors within the machine in order to transmit them in a bundled form via a single data line to an external evaluation unit. In particular, the sensor module is provided with a corresponding communication interface for connection to a digital bus line in order to be able to transmit the digitized sensor values to the external evaluation unit via the bus system. The integration of the sensor module and its gateway functionality eliminates the need for separate data lines for the installed sensors to the external evaluation unit. Instead, the routing of separate lines is limited to the wiring within the machine. A single communication line from the sensor module to the evaluation unit is sufficient, which greatly simplifies the wiring effort and thus the entire installation and commissioning of the machine. Furthermore, a more robust data transmission system can be provided, as the digitized measured value transmission guarantees better error protection mechanisms.

According to an advantageous embodiment of the invention, the shared digital transmission path between the sensor module and the external evaluation unit can be a four-wire bus system. Ideally, the power supply to the machine, especially the submersible motor, is also provided via the four-wire bus system, which further simplifies cabling. In addition to the power supply, the exchange of any control signals from the external evaluation unit to the machine can also be provided.

The sensor module can also incorporate one or more integrated sensors, such as a vibration sensor located directly on the circuit board. The vibration measurements can also be processed or digitized by the sensor module's integrated controller and transmitted to the external evaluation unit via the digital transmission path.

The connection interfaces, e.g., in the form of cable terminals, are used to connect different sensor types. The machine preferably includes one or more temperature sensors that record temperature measurements at safety-critical points of the machine and transmit them to the sensor module via the connection terminals. The use of different temperature sensors is conceivable, e.g., PTC (Positive Temperature Coefficient) thermistors and Pt100 sensors. Bimetallic sensors can also be used. The installed temperature sensors are preferably used to monitor the temperature of a bearing. particularly the motor bearing or a bearing support of the submersible motor. Alternatively or additionally, temperature sensors can be installed to monitor the motor temperature, particularly in the area of or within the stator windings. PTC thermistors, for example, can be embedded directly in the stator winding; an additional Pt100 sensor can be installed on the motor outside the stator winding.

Motor temperature monitoring plays a key role in operational safety, as excessively high winding temperatures can cause the windings to catch fire and damage the motor. Motor temperature monitoring is particularly important for applications in potentially explosive atmospheres. Therefore, the sensor module preferably evaluates the sensor signal from a temperature sensor, particularly from sensors used to monitor motor temperature. The microcontroller is further configured to communicate the evaluation result to the evaluation unit via the digital transmission path. Ideally, the evaluation unit includes a corresponding relay circuit to interrupt the power supply to the submersible motor if the temperature develops too high. It is particularly preferred for the microcontroller to compare the incoming measurement signal from the PTC sensor with a limit value and communicate the result to the external evaluation unit. It is also conceivable for the comparison result to be communicated to the external evaluation unit via two separate transmission channels.

In addition to one or more temperature sensors, the sensors can also include one or more conductive probes, for example, to detect fluid accumulations or fluid changes within the machine. Such probes are often used to detect leaks. One or more oil sensors can also be installed in the machine. These also operate according to the conductive measuring principle and detect the quality of the oil, particularly any contamination of the oil, such as an undesirable water content in the oil. Such leakage and/or oil sensors can also be connected to the sensor module. An oil sensor is preferably used to monitor a mechanical seal, in particular to detect the oil condition of the oil in the mechanical seal chamber. In particular with submersible motor pumps and/or tachomotor agitators, it can be specified that the oil sensor must be implemented according to the ignition protection type intrinsic safety in order to enable the oil sensor to be used in a hazardous location. Against this background, it is necessary that the oil sensor does not contain any electrical components, at least in the measuring area, i.e. within the mechanical seal chamber. For this reason, the necessary sensor electronics, i.e. the electronics for generating voltage between the measuring electrodes, are preferably integrated into the sensor module. The installed oil sensor therefore only comprises two electrodes in the measuring point area, and the voltage generated between the electrodes is generated by the sensor electronics in the sensor module.

Furthermore, it is provided that the sensor electronics actively limits the energy level in the measuring circuit, in particular by means of a Zener barrier integrated into the sensor module, preferably consisting of three bi-directional suppressor diodes in parallel for voltage limitation, a resistor network for protecting the diodes and a resistor network for current limitation.

The connecting cable between the oil sensor and the sensor module can be routed outside the housing. The oil sensor, i.e., the electrode, can be inserted into the oil chamber of the sealing system via a sealed connection. The connecting cable is thus largely routed outside the housing and only enters the housing immediately adjacent to the housing section containing the sensor module.

The sensor module is ideally integrated into a dedicated electronics housing of the machine, with the electronics housing being located on the periphery of the motor housing. The electronics housing and motor housing are preferably not insulated from each other. In addition to the machine according to the invention, the present invention also relates to a system for monitoring at least one machine according to the invention, wherein such a system is characterized by at least one external evaluation unit that is communicatively connected to the sensor module of at least one machine via the shared digital transmission path. Such an evaluation unit receives the sensor data forwarded by the sensor module and evaluates the sensor data for monitoring and analyzing the machine. It can also be provided that such an evaluation unit has a communication interface for communicating with other devices via TCP/IP or Modbus.

Further advantages and features of the invention will be explained in more detail below using an exemplary embodiment illustrated in the figures. They show:

Figure 1: a sectional view through a submersible motor of the machine according to the invention and

Figure 2: an external view of a submersible mixer with built-in oil sensor.

The invention is described below using an example of the machine according to the invention in the form of a submersible mixer. Figure 1 shows a longitudinal section through the submersible motor of the machine according to the invention. A temperature sensor 11 for monitoring the bearing temperature is installed within the motor housing 24 in the area of a first axial bearing 18. The temperature sensor 11 is a Pt100 type sensor and is screwed into the bearing carrier 25 of the motor housing 24. Alternatively or additionally, the temperature sensor 11 could also be arranged in the area of a second axial bearing 26. The axial bearings 18, 26 can be designed as floating or fixed bearings.

For leakage monitoring, a conductive probe 12 is located below the second axial bearing 26, which is glued into a probe plug screw 19. The Screw 19 can be screwed into the front side of the motor housing 24 from the outside, whereby the probe 12 protrudes into the engine compartment and can detect fluid accumulations in the motor housing 24.

In the area of the stator 20 of the motor, a first motor temperature sensor 13 of the Pt100 type is applied externally to the motor winding 15. A PTC thermistor 14 is embedded in the winding 15. Alternatively, the motor temperature sensor 13 can also be embedded in the winding 15.

The sensor connections of the sensors 11, 12, 13 and 14 run within the motor housing 24 to an electronics housing 17 which sits circumferentially on the motor housing 24. The electronics housing 17 and the motor housing 24 are connected to one another via an opening 27, which simplifies the cable feedthrough.

The sensor module 10, which includes several sensor inputs in the form of connection terminals, is located in the electronics housing 17. The sensors 11, 12, 13, and 14 transmit the measurement signals to the sensor module 10. A microcontroller located on the circuit board of the sensor module 10 converts the received sensor signals into digital signals and transmits them to an external evaluation unit via a digital four-wire bus. The sensor module 10 therefore bundles at least a portion of the incoming sensor measurement signals and transmits them bundled to the outside via a digital communication bus, so that the communicative connection of the sensors 11, 12, 13, and 14 to an external evaluation unit can now be established via a single digital line.

The four-wire bus can also be used to provide the power supply for the submersible motor shown, so that the motor can be controlled via the external evaluation unit.

A special feature applies to the temperature monitoring of the motor. The motor PTC circuit 14 is monitored via two independent measuring paths. Channel 1 is Here, a microcontroller-based monitoring system, while channel 2 is purely analogue monitoring. The PTC state determined by sensor module 10 is transmitted to the PTC relay in the external evaluation unit via two transmission channels. The PTC relay is switched off immediately and locked (= restart lock) when the nominal switch-off temperature, NAT, is reached. The PTC relay operates according to the closed-circuit current principle, i.e., it switches automatically after the supply voltage to the submersible motor is applied, provided the motor PTC is in a "good state" (temperature < NAT, no sensor error, etc.) and no lock is present. A monitoring lock can only be canceled manually on the evaluation unit, e.g. using the integrated reset button, and then only when the motor PTC is in a "good state". In principle, it is possible to integrate the PTC relay into sensor module 10.

Figure 2 shows an external view of the submersible motor with the attached hydraulic unit 21, which includes a mechanical seal at the axial end for sealing the outgoing shaft 16 rotating about the rotational axis A. A corresponding oil sensor 22 is inserted into the sealing chamber, which is inserted into the sealing chamber from the outside via a suitable seal. The oil sensor

22 is connected to the sensor module 10 via a connecting line 23, which runs on the outside of the hydraulic part 21 and the motor housing 24 in the direction of the electronics housing 17. Both the sensor 22 and the connecting line

23 are located in the potentially explosive area of the machine.

The oil sensor 22 operates conductively. The electronics in the sensor module 10 apply an alternating voltage between two electrodes located in the measuring area of the mechanical seal. Depending on the electrical conductivity of the surrounding medium (oil or additional water in the event of a leak), this voltage causes a current to flow between the electrodes. The resulting electrical resistance value is determined and evaluated by the sensor module 10.

The limitation of the energy in the measuring circuit of the sensor 22 is achieved by a Zener barrier integrated in the sensor module 10. The Zener barrier consists of Three bidirectional suppressor diodes connected in parallel to limit the voltage. A resistor network consisting of four 3.32 kΩ resistors serves to protect the diodes, while another resistor network consisting of four 3.3 kΩ resistors limits the current flow in the measuring circuit. All necessary electronic components for voltage generation and measured value processing are thus fully integrated into the sensor module 10 to ensure a so-called explosion-proof barrier for the sensor 22.

The external evaluation unit, which is connected to the sensor module 10 via the four-wire bus system, is used to evaluate the individual sensor signals and to control the submersible motor accordingly. The bus system also provides the power supply for the submersible motor. Furthermore, the evaluation unit can transmit the sensor data or evaluation results to higher-level control or regulation units via an additional communication interface.

Claims

Patent claims 1. Machine with an integrated submersible motor, in particular a submersible mixer or a submersible pump, with a housing, a plurality of integrated sensors (11, 12, 13, 14, 22) and a sensor module (10) installed within the housing (17), wherein the sensor module (10) has a plurality of measured value inputs for receiving any measuring signals from the sensors (11, 12, 13, 14, 22) and comprises a microcontroller which is configured to digitize the received measured values of the connected sensors (11, 12, 13, 14, 22) and to transmit them to a remote evaluation unit via a common digital transmission path. 2. Machine according to claim 1, characterized in that the common digital transmission path is provided via a four-wire bus, wherein the power supply of the submersible motor is preferably also provided via the four-wire bus. 3. Machine according to claim 1 or 2, characterized in that the sensor module (10) comprises an integrated vibration sensor, wherein the sensor values of the vibration sensor are also processed by the controller and transmitted via the digital transmission link. 4. Machine according to one of the preceding claims, characterized in that the sensors comprise one or more temperature sensors (11, 12, 13, 14), in particular sensors of the PTC, Pt100 or bimetal type. 5. Machine according to claim 4, characterized in that the temperature sensors (11, 12, 13, 14) serve to monitor the temperature of a bearing and/or to monitor the motor temperature, wherein at least one temperature sensor (13, 14) for motor temperature monitoring is in particular embedded in the motor winding (15) and/or attached externally to the motor winding (15). 6. Machine according to claim 4 or 5, characterized in that the sensor module (10) is configured to evaluate the measurement signal of at least one temperature sensor (14), in particular to evaluate the measurement signal of a temperature sensor (14) for monitoring the engine temperature, the evaluation result being transmitted to the remote evaluation unit. 7. Machine according to one of claims 4 to 6, characterized in that the sensor module (10) is configured to carry out the evaluation by comparing the measured value with a limit value and transmits information to the external evaluation unit as to whether the limit value is exceeded or not. 8. Machine according to one of claims 6 or 7, characterized in that the result of the evaluation is transmitted to the external evaluation unit by means of two transmission channels. 9. Machine according to one of the preceding claims, characterized in that the sensors comprise one or more conductive probes (12) to detect leaks in the housing. 10. Machine according to one of the preceding claims, characterized in that the sensors comprise an oil sensor (22) for detecting the condition of the oil in the mechanical seal chamber of a mechanical seal, the oil sensor (22) preferably being a conductive probe. 11 . Machine according to claim 10, characterized in that the oil sensor (22) does not contain any electronic components in the area of the measuring point or within the mechanical seal chamber and the necessary sensor electronics are integrated into the sensor module (10), in particular a circuit for supplying energy to the oil sensor (22). 12. Machine according to claim 10 or 11, characterized in that the connecting line (23) between the oil sensor (22) and the sensor module (10) is arranged predominantly on the outside of the housing. 13. Machine according to one of the preceding claims, characterized in that the sensor module (10) is arranged integrated in an electronics housing (17) of the machine 14. System for monitoring at least one machine according to one of the preceding claims, characterized in that the system has an evaluation unit arranged externally to the at least one machine, which is connected to the sensor module (10) of the at least one machine via the digital transmission path and is configured to monitor the received sensor data of the machine. 15. System according to claim 14, characterized in that the evaluation unit has at least one digital output, in particular suitable for communication via TCP/IP and/or Modbus, in order to transmit sensor and/or evaluation data to at least one other device.