Centrifugal separator device, system and method for energy harvesting in centrifugal separator device

Abstract

The invention relates to a centrifugal separator device, a system and a method for energy harvesting in a centrifugal separator device. The present invention relates to a centrifugal separator device, the device comprising: an energy converter positioned near a rotor of the centrifugal separator device and configured to collect non-electrical energy collected from the centrifugal separator and to convert it into electrical energy; a sensor configured to obtain a parameter associated with operation of the centrifugal separator, where the sensor includes a processor configured to generate corresponding data; wherein the sensor is electrically connected with the energy converter, and the energy is supplied by the electric energy generated by the energy converter. The invention also relates to a method and system for energy harvesting in a centrifugal separator device.

Description

TECHNICAL FIELD

[0001] One aspect of the present disclosure relates to a centrifugal separator device. Other aspects of the present disclosure relate to methods and systems for energy harvesting in a centrifugal separator device. BACKGROUND

[0002] A centrifugal separator is a device that works on the principle of separating various components of a fluid or separating various components from a fluid using centrifugal force. This is achieved by rotating the fluid at high speed in the centrifugal separator, thereby separating fluids of different densities or separating liquids from solids. In the rotor of the centrifugal separator, the more dense matter and particles (e.g. particulate contaminants) move outwards in the radial direction and compact along the wall of the rotor to form a dense cake. At the same time, the less dense medium (e.g. clean fluid) is displaced and moves to the center of the rotor.

[0003] Although the centrifugal separator itself can not require the use of electricity, the equipment used for the maintenance and operation of such centrifugal separators, such as sensors, often require a power source. This is troublesome because a power outlet must be connected and / or a battery must be (re)placed and their lifetime must be monitored. Therefore, there is a need to provide an improved centrifugal separator device; and methods and systems for energy harvesting in a centrifugal separator device.

[0004] In more specific cases, the maintenance of removing the dense cake from the wall can involve removing the cover of the rotor and subsequently removing the rotor from its bearing (e.g. spindle).

[0005] On the one hand, such maintenance operations are often not necessary because the accumulation of the dense cake on the rotor wall can not yet have reached a stage where it is necessary / required to be removed. However, using conventional maintenance methods, the stage of the dense cake on the rotor wall is often unknown to the operator until after the centrifugal separator has been disassembled, which can lead to unnecessary disassembly of the centrifugal separator. Such unnecessary disassembly can lead to unnecessary downtime of the centrifugal separator, waste of manpower and reduced efficiency. On the other hand, if the rotor is allowed to continue operating for too long, the dense cake can fall into the clean fluid, thereby contaminating the clean fluid, which can lead to inefficient separation. Furthermore, the dense cake can collapse and restrict oil flow, thereby affecting the performance of the rotor.

[0006] Therefore, there is also a need to provide an improved maintenance method. SUMMARY

[0007] One aspect of the present disclosure relates to a centrifugal separator device. The centrifugal separator device can include a centrifugal separator. The centrifugal separator can include a stationary housing defining an enclosure. The centrifugal separator can include a rotor including a wall defining an interior volume, wherein the rotor can be rotatably mounted in the enclosure to rotate about an axis of rotation, optionally a longitudinal axis of rotation. The centrifugal separator can include a feed passage to supply a contaminated fluid including particulate contaminants and to allow the contaminated fluid to flow to the interior volume of the rotor. The centrifugal separator can include an egress opening to release cleaned fluid from the centrifugal separator, wherein the rotor outlet passage can be configured to allow the cleaned fluid to flow out in a direction including a tangential component relative to the axis of rotation, thereby causing an angular displacement of the rotor when the contaminated fluid is applied via the feed passage at a fluid pressure above a fluid pressure threshold, thereby rotating the rotor and generating non-electrical energy during rotation. The centrifugal separator device can further include an energy converter positioned proximate the rotor and configured to collect and convert the non-electrical energy collected from the centrifugal separator into electrical energy. The centrifugal separator device can further include one or more sensors configured to obtain parameters associated with operation of the centrifugal separator. The one or more sensors can include a processor configured to generate corresponding data. The one or more sensors can be operably connected with the energy converter to be powered by the electrical energy generated by the energy converter.

[0008] According to various embodiments, the non-electrical energy collected from the centrifugal separator can be mechanical energy.

[0009] According to various embodiments, the mechanical energy can be vibrational energy.

[0010] According to various embodiments, the energy converter can include a piezoelectric transducer configured to be subjected to mechanical vibrations.

[0011] According to various embodiments, the energy converter can include an AC-DC rectifier configured to generate a DC voltage.

[0012] According to various embodiments, the non-electrical energy collected from the centrifugal separator can be thermal energy.

[0013] According to various embodiments, the energy converter can include a thermoelectric generator configured to be subjected to the influence of a heat source and a heat sink.

[0014] According to various embodiments, the energy converter can include a DC-DC converter configured to adjust the DC voltage generated by the energy converter.

[0015] According to various embodiments, the energy converter can include a capacitor arranged to smooth the DC voltage to reduce ripple.

[0016] According to various embodiments, the centrifugal separator device can further include an energy storage device.

[0017] According to various embodiments, the sensor can comprise a rotation sensor configured to measure a change in a rotational frequency of the rotor and to generate corresponding rotor rotation data.

[0018] According to various embodiments, the rotor rotation data and the transient control parameter for controlling the applied fluid pressure can be configured for determining a load of accumulated particulate contamination separated from the cleaned fluid caused by particulate contamination deposited on an inner surface of the wall. The load of the rotor can be determined based on the rotor rotation data and the transient control parameter.

[0019] One aspect of the present disclosure relates to a method for energy harvesting in a centrifugal separator device as defined herein. The method can comprise the step of providing a centrifugal separator device as described herein. The method can comprise the step of positioning an energy converter in a position suitable for harvesting non-electrical energy. The method can comprise the step of converting the non-electrical energy into electrical energy. The method can comprise the step of providing the electrical energy to a sensor.

[0020] One aspect of the present disclosure relates to a system for energy harvesting in a centrifugal separator device. The system can comprise a centrifugal separator device as described herein. An energy converter can be configured to harvest non-electrical energy generated during rotation of a rotor. The energy converter can be configured to convert the non-electrical energy into electrical energy. The energy converter can be configured to utilize the electrical energy to power a sensor. BRIEF DESCRIPTION OF DRAWINGS

[0021] The attached drawings illustrate: Figure 1 is a centrifugal separator device according to various embodiments; Figure 2 is a thermoelectric generator according to various embodiments; Figure 3 is a method for energy harvesting in a centrifugal separator device according to various embodiments; Figure 4 is a system for energy harvesting in a centrifugal separator device according to various embodiments; Figure 5 is a graph illustrating one example of determining a load of a rotor of a centrifugal separator device according to various embodiments; Figure 6 is an illustration of curve fitting according to various embodiments. DETAILED DESCRIPTION

[0022] The following detailed description references the drawings, wherein: The embodiments described below are presented by way of illustration and should not be construed as limiting the scope of the disclosure. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments can be utilized and that structural and logical changes can be made without departing from the scope of the present disclosure. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0023] Embodiments described in the context of one of the centrifugal separator device, the method for energy harvesting, and the system for energy harvesting in a centrifugal separator device are similarly effective for another of the centrifugal separator device, the method for energy harvesting, and the system for energy harvesting in a centrifugal separator device.

[0024] Figure 1 A centrifugal separator device 100 is illustrated in accordance with various embodiments. As shown therein, the centrifugal separator device 100 can include a stationary housing 110. The stationary housing 110 can have a fixed position, such as with respect to an engine (e.g., a motor, such as an electric motor) or a fluid cleaning system. Other portions of the centrifugal separator can move with respect to the stationary housing 110. The stationary housing 110 can have a cylindrical shape. A top edge of the stationary housing 110 can be rounded, such that a top of the stationary housing 110 can resemble a bell shape. The stationary housing 110 can define an enclosure within the stationary housing 110. In other words, the stationary housing 110 can be configured to house the remaining components of the centrifugal separator device 100 therein.

[0025] According to various embodiments, a material of the stationary housing 110 can include or be a metal or a metal alloy. For example, the material of the stationary housing 110 can include aluminum or an aluminum alloy. In some embodiments, the material of the stationary housing 110 can be diamagnetic.

[0026] The centrifugal separator device 100 can further comprise a rotor 120 which is rotatably mounted (e.g. about an axis of rotation) in the enclosure defined by the stationary housing 110. The axis of rotation can be a longitudinal axis of rotation. In other words, while the stationary housing 110 can be configured to be fixed to a structure, the rotor 120 can be configured to be in rotational motion relative to the stationary housing 110 (e.g. about the axis of rotation). The rotor 120 can be substantially enclosed within the stationary housing 110. The rotor 120 can have a cylindrical shape and can follow the contour of the stationary housing 110 in a diameter of the cylinder which is smaller than the diameter of the stationary housing 110. The rotor 120 can comprise a wall 122 defining an inner volume. The inner volume can surround the axis of rotation (e.g. in a rotationally symmetric manner). Thus, the wall 122 can be positioned towards the center of the rotor, i.e. away from the stationary housing 110. In some embodiments, the rotor 120 can be rotatably mounted within the stationary housing 110 by being mounted on a main shaft 124.

[0027] According to various embodiments, the material of the rotor 120 can comprise or be a metal or a metal alloy. For example, the material of the rotor 120 can comprise aluminum or an aluminum alloy. Advantageously, the material of the rotor 120 can be diamagnetic.

[0028] The centrifugal separator device 100 can further comprise a feed passage 130. The feed passage 130 can be defined by an inner wall 132 of the main shaft 124 and can extend in an axial direction (identified in the following as direction z) within the rotor 120. The feed passage 130 can be configured to supply a contaminated fluid comprising particulate contaminants. In particular, the feed passage 130 can allow the contaminated fluid comprising particulate contaminants to flow through the feed passage 130 and into the inner volume of the rotor 120. Figure 1

[0029] The contaminated fluid comprising particulate contaminants can be referred to as a fluid and particulate contaminants dissolved or dispersed therein. According to various embodiments, the contaminated fluid comprising particulate contaminants enters or is pumped into the feed passage 130. In other words, the contaminated fluid entering the rotor 120 can generally contain particulate contaminants. Then, under the application of a centrifugal force, the particulate contaminants in the contaminated fluid can be cleaned. Additionally or alternatively, under the application of a centrifugal force, the particulate contaminants can be removed (e.g. separated) from the contaminated fluid before the fluid exits the rotor 120. The fluid exiting the rotor 120 can be referred to as a cleaned fluid, which contains relatively less contaminants compared to the contaminated fluid comprising particulate contaminants. Thus, a fluid comprising less particulate contaminants than the contaminated fluid can be referred to as a cleaned fluid. The cleaning can be performed during one or more cycles of the fluid through the rotor. The fluid can comprise or consist of an inorganic fluid, e.g. which can be water. Alternatively, the fluid can be an organic fluid, an organic fluid, e.g. which can be a hydrocarbon, e.g. oil.​

[0030] A contaminated fluid including particulate contaminants can enter the feed passage 130 of the centrifugal separator under an applied fluid pressure and can be further directed into the rotor 120 via an inlet passage, e.g., a lateral bore 134. The rotor 120 can be completely filled with the contaminated fluid including particulate contaminants and can then allow the cleaned fluid to exit through the exit opening 140 and into a rotor outlet channel 150 fitted in a bottom portion of the rotor 120. The cleaned fluid can exit through the exit opening 140 with a tangential component relative to the rotational axis, e.g., such that a torque can be generated in an opposite direction of the exit opening of the cleaned fluid. The torque can generate a rotation of the rotor 120. This rotation can in turn generate a centrifugal force in the contaminated fluid including particulate contaminants within the rotor 120. As the particulate contaminants enter the rotor 120 with the contaminated fluid, they can be subjected to this centrifugal force. Under the action of this centrifugal force, the particulate contaminants can move radially outward to the inner wall 122 of the rotor 120 and, e.g., can be deposited along the inner wall 122 as a layer of contaminants. With the continuous accumulation of these particulate contaminants under the centrifugal force, the layer of contaminants can be compacted and form a dense mass (not shown). The dense mass can also be referred to as a load of accumulated particulate contaminants configured to be separated from the cleaned fluid.

[0031] To monitor parameters associated with the operation of the centrifugal separator, the centrifugal separator device 100 can further include one or more sensors 170. The one or more sensors 170 can detect one or more parameters that can affect the optimal performance, efficiency, and safety of the separation process during the operation of the centrifugal separator device 100. The detection of the one or more parameters can include measuring the one or more parameters. The detection of the one or more parameters can be used to control such parameters associated with the operation of the centrifugal separator.

[0032] The one or more sensors 170 can include physical sensors, which can include hardware-based sensors. The one or more sensors 170 can include soft sensors, which can include software-based algorithms and models. The one or more sensors 170 can further include a combination of hard sensors and soft sensors. The one or more sensors 170 can include one or more wireless sensors. For example, the parameters associated with the operation of the centrifugal separator can include a rotational frequency of the rotor 120. The parameters associated with the operation of the centrifugal separator can include a frequency of the rotor 120. The parameters associated with the operation of the centrifugal separator can include a temperature of the contaminated fluid. The parameters associated with the operation of the centrifugal separator can include a flow rate of the contaminated fluid. The parameters associated with the operation of the centrifugal separator can include a pressure of the contaminated fluid.

[0033] Thus, the hardware-based sensors 170 associated with monitoring such parameters can include a rotation sensor. The hardware-based sensors 170 associated with monitoring such parameters can include a temperature sensor. The temperature sensor can include one or more of a thermocouple and a resistance temperature detector (RTD). The hardware-based sensors 170 associated with monitoring such parameters can also include a vibration sensor. The vibration sensor can include one or more of an accelerometer and a velocity sensor. The hardware-based sensors 170 associated with monitoring such parameters can also include a pressure sensor. The pressure sensor can include one or more of a piezoelectric sensor and a strain gauge sensor. The hardware-based sensors 170 associated with monitoring such parameters can also include a flow sensor. The flow sensor can include one or more of a turbine flow meter and a Coriolis flow meter. Such sensors can require electricity to operate.

[0034] The soft sensors 170 can include model-based algorithms configured to estimate and predict process parameters that are difficult or expensive to measure directly. Soft sensors can also be referred to as virtual sensors. They can include one or more of Kalman filters and observer-based techniques that use a system model to estimate the state and output of a decoupled process. The soft sensors 170 can also include one or more of machine learning models. The machine learning models can include one or more of regression models and neural networks. The soft sensors 170 can also include one or more of data fusion techniques, such as sensor fusion algorithms.

[0035] It can be cumbersome to provide this electricity to the sensors 170 of the centrifugal separator apparatus 100 (which otherwise can operate without the use of electricity), requires maintenance (e.g., replacing batteries), and the effort is proportionally high for the small amount of electricity typically required by the sensors. Thus, the present disclosure provides a centrifugal separator apparatus 100 in which non-electrical energy produced during operation of the centrifugal separator can be converted into electrical energy, which in turn is provided to the one or more sensors 170. To collect this non-electrical energy and convert it into electrical energy, an energy converter 160 is provided that is configured to convert the non-electrical energy collected from the centrifugal separator into electrical energy. Although Figure 1 The energy converter 160 in FIG. 1 is exemplarily placed at about 75% of the height of the stationary housing 110 on the stationary housing 110, but the energy converter 160 can be placed at any location of the centrifugal separator suitable for collecting non-electrical energy produced during operation of the centrifugal separator.

[0036] Advantageously, by providing an energy converter 160 configured to convert the non-electrical energy collected from the centrifugal separator into electrical energy, the problems associated with conventionally providing this electricity to the sensors of the centrifugal separator apparatus 100 are avoided. Moreover, the non-electrical energy can be collected and not lost, which is more environmentally friendly.

[0037] For example, the non-electrical energy provided by operation of the centrifugal separator can include mechanical energy. For example, the mechanical energy can be due to vibrations during operation. These vibrations can be caused by slight imbalances and occur frequently during operation. As such, the energy can also be referred to as vibration energy. Vibration energy can be harvested through various methods and materials, each having its own mechanisms and applications. Examples of harvesting vibration energy include, but are not limited to, piezoelectric energy harvesting, electromagnetic energy harvesting, electrostatic energy harvesting, triboelectric energy harvesting, and magnetostrictive energy harvesting. An appropriate harvesting method can be selected based on the vibration characteristics of the centrifugal separator. The vibration characteristics can include the frequency and amplitude of vibrations during operation of the centrifugal separator.

[0038] In one embodiment, vibration energy can be harvested using a piezoelectric transducer 180. The piezoelectric transducer 180 can include a piezoelectric material. The piezoelectric material can include one or more of quartz, piezoelectric ceramic materials, and polyvinylidene fluoride (PVDF). Examples of piezoelectric ceramic materials can include lead zirconate titanate (Pb[Zr (x) Ti (1-x) ]03) (PZT). The piezoelectric transducer 180 can be positioned (e.g., fixed) at a location where it can experience mechanical vibrations. When the piezoelectric material deforms due to vibrations, it can generate an electric charge. This electric charge can be harvested and stored in a capacitor or storage device. Additionally or alternatively, the electric charge can be used to power the one or more sensors 170.

[0039] The electric charge or electricity generated by the piezoelectric transducer 180 can be an AC voltage or current, as the stress and strain applied to the material can vary over time. This can cause the output voltage or current to alternate. Accordingly, in some embodiments, the centrifugal separator apparatus 100 can also include an AC-DC rectifier 182. This AC-DC rectifier 182 can convert this alternating voltage to a unidirectional DC voltage. Advantageously, the generation of a DC voltage can facilitate the operation of the one or more sensors 170 and electronic circuitry within storage devices such as batteries and capacitors.

[0040] The non-electrical energy generated from the operation of the centrifugal separator can include thermal energy. In one embodiment, the thermal energy can be generated as a result of thermodynamic changes during the operation of the centrifugal separator. In these embodiments, the thermal energy can be harvested through the use of, for example, a thermoelectric generator (TEG). This can involve the use of the Seebeck effect to convert heat (thermal energy) into electrical energy. The Seebeck effect utilizes a temperature difference across a centrifugal separator and ambient air to generate a voltage. In brief, the effect is based on the generation of an electric current by joining two different conductive materials together to form a circuit, where their junctions are maintained at different temperatures. The components of a thermoelectric generator using the Seebeck effect can include thermoelectric materials. These thermoelectric materials can include materials with a high Seebeck coefficient. The thermoelectric materials can also include materials with a low thermal conductivity. They also include materials with a high electrical conductivity. Thus, the thermoelectric generator can include materials such as bismuth telluride (Bi2Te3), lead telluride (PbTe), and silicon-germanium (SiGe) alloys. Further, P-N junctions can be arranged by placing many p-type and n-type semiconductor elements in pairs. The pairs can be connected in electrical series and thermal parallel. The temperature gradient required to harvest the thermal energy can involve a hot source and a heat sink. The hot source can include waste heat generated from the operation of the centrifugal separator. The heat sink can include ambient air or a cooling system. During the harvesting of the thermal energy, a temperature difference can be established between the hot side and the cold side of the thermoelectric material, and this temperature difference can cause charge carriers (electrons for n-type and holes for p-type) in the material to diffuse from the hot side to the cold side. This movement of charge carriers can generate a voltage across the material. The voltage generated by each thermocouple pair can be small, but when many pairs are connected in series, the voltages add up, resulting in an output voltage that can be used.

[0041] Figure 2 is a schematic diagram of a thermoelectric generator 200 as an example of one embodiment of the present disclosure. Shown therein is an arrangement of p-type semiconductor elements 210 and n-type semiconductor elements 220 in pairs, leaving gaps for conductor tabs 230. The p-type and n-type semiconductor elements 210, 220 are sandwiched between two substrates, one of which is shown as substrate 240. One of the substrates 240 is positioned at the hot side (e.g., hot source) of the thermoelectric generator 200, while the other side of the thermoelectric generator 200 is positioned at the cold side (e.g., heat sink) of the thermoelectric generator 200. The substrate 240 is illustrated as a ceramic material, but can alternatively include one or more of a polymeric material, a metallic material, and a glass. In the case where the substrate 240 is a ceramic substrate, the material can be selected from the group consisting of aluminum oxide, aluminum nitride, silicon carbide, and combinations thereof. The voltage generated by the thermoelectric generator 200 is harvested at + and - poles 250 / 260.

[0042] Unlike the electrical energy converted by the piezoelectric transducer 180, the electrical energy obtained from the TEG can be a DC voltage. Thus, when using a TEG as the energy converter 160, an AC-DC rectifier can not be needed. However, in some embodiments, a DC-DC converter can be used to adjust the voltage level to match the needs of the one or more sensors 170.

[0043] Non-electrical energy produced by the operation of the centrifugal separator can also include light energy. The light energy can be collected by one or more photovoltaic cells. The photovoltaic cells can include one or more of silicon-based cells, dye-sensitized solar cells, organic photovoltaic cells, and perovskite solar cells. Additionally, the light energy can be collected by a concentrated solar power system by using focused sunlight to produce thermal energy, which can then be converted to electricity, as detailed above.

[0044] Non-electrical energy produced by the operation of the centrifugal separator can also include acoustic energy. The acoustic energy can include the same or similar characteristics of mechanical energy. Thus, the acoustic energy can be collected similarly to vibrational energy, as detailed above. Thus, the collection of acoustic energy can include the use of one or more of piezoelectric energy harvesting, electromagnetic energy harvesting, electrostatic energy harvesting, triboelectric energy harvesting, and magnetostrictive energy harvesting.

[0045] The placement of the energy converter 160 can depend on the nature of the energy converter 160 and, in general, can be near the rotor 120. For example, in the case where the energy converter 160 converts mechanical energy to electrical energy, it can be advantageous to place the energy converter 160 in contact with one or more of the rotor 120 and the stationary housing 110. In some embodiments, the energy converter 160 for converting mechanical energy to electrical energy can be placed at a location where the vibrations produced by the rotor 120 are maximized.

[0046] In the case where the energy converter 160 converts thermal energy to electrical energy, it can be advantageous to place the energy converter 160 in contact with one of a heat source and ambient air or a cooling system. It should be noted that in this regard Figure 1The placement of the energy converter 160 in the middle is one example, and it is to be understood that the placement of the energy converter 160 that converts thermal energy into electrical energy can need to be in contact with two surfaces, as further described below. In some embodiments, the energy converter 160 for converting thermal energy into electrical energy can be placed at a location where the temperature gradient between the heat source and the heat sink is maximized. In other words, the energy converter 160 for converting thermal energy into electrical energy can be placed in contact with a hot surface and a cold surface, where the heat is generated by the operation of the centrifugal separator. In this context, the terms “hot” and “cold” are intended to be defined relative to each other, where a “hot surface” refers to a surface that has a higher temperature compared to a surface referred to as a “cold surface”. An example of a hot surface can be the stationary housing 110, and an example of a cold surface can be a radiator. One example of a radiator is a metal heat sink.

[0047] In some embodiments, the DC voltage generated by the conversion from non-electrical energy as described above can also be affected by a capacitor 162. The capacitor 162 can have the function of smoothing the DC voltage to reduce the ripple in the voltage.

[0048] In some embodiments, the energy converter 160 can also include a voltage rectifier 164. The voltage rectifier 164 can have the function of ensuring that the DC voltage generated by the conversion from non-electrical energy remains stable and within a desired range.

[0049] In some embodiments, the centrifugal separator apparatus 100 can additionally include an energy storage device 166. The energy storage device 166 can be a rechargeable battery or a supercapacitor. The energy storage device 166 can have the function of storing the DC voltage generated by the conversion from non-electrical energy for later use. The energy storage device 166 can be electrically connected with both the energy converter 160 and the one or more sensors 170. For example, the energy storage device 166 can be connected with both the energy converter 160 and the one or more sensors 170 via a cable.

[0050] In particular embodiments, the one or more sensors 170 can include a radio frequency (RF) attenuation monitoring system. The RF attenuation monitoring system can use RF signals that are absorbed or scattered by the material within the centrifugal separator to provide real-time data. The real-time data can include data that gives an indication about the contents and operating state of the centrifugal separator. In further detail, and in some embodiments, the RF attenuation monitoring system can use a transmitter to generate and emit RF signals of a particular frequency. Subsequently, RF receivers can detect the attenuated RF signals after they have passed through the separator. The RF attenuation monitoring system can then use antennas to transmit and receive the RF signals. As such, these antennas can be placed externally and / or internally, depending on the design of the centrifugal separator and the monitoring needs. The RF attenuation monitoring system can also include a processor (further defined below), which can include a signal processing unit. The signal processing unit can analyze the received RF signals to extract corresponding data about the contents and state of the centrifugal separator. In one embodiment, the RF attenuation monitoring system can also include a control and display system. The control and display system can allow an operator to monitor the real-time data and receive alerts about the operation of the centrifugal separator.

[0051] In another particular embodiment, the sensor 170 can be a rotation sensor 172, which can be configured to obtain a change in the rotational frequency of the rotor and produce corresponding rotor rotation data. According to various embodiments, the sensor 170 can be attached to the centrifugal separator. The attachment of the sensor 170 to the centrifugal separator can be a non-removable attachment. The one or more sensors 170 can be electrically connected with both the energy storage device 166 (if present) and the energy converter 160. For example, the one or more sensors 170 can be connected with the energy storage device 166 (if present) and the energy converter 160 via a cable.

[0052] The one or more sensors 170 can also include a processor, also referred to as a server. The processor can be configured to produce data corresponding to parameters associated with the operation of the centrifugal separator. As such, the corresponding data can represent values of the parameters associated with the operation of the centrifugal separator and / or differences in the parameters over time. In some embodiments, the parameters can include transient control parameters, which are described further below.

[0053] The data corresponding to parameters associated with the operation of the centrifugal separator can include one or more of a particular temperature, a particular pressure, a particular rotational frequency, and a flow rate of the contaminated fluid. The data corresponding to parameters associated with the operation of the centrifugal separator can also include a change in one or more of a particular temperature, a particular pressure, a particular rotational frequency, and a flow rate of the contaminated fluid over time.

[0054] As used herein, the term "server" or "processor" can include a single stand-alone computer, a single dedicated server, multiple dedicated servers, and / or a virtual server running on a larger server network and / or cloud-based service. The processor can include an integrated circuit (IC) chip, such as an application-specific integrated circuit (ASIC) chip.

[0055] In embodiments where the sensor 170 is a rotational sensor 172, the rotational sensor 172 can be selected from a Hall effect sensor, a magnetoresistive sensor, a giant magnetoresistive sensor, or a combination thereof. The rotational sensor 172 can be a Hall effect sensor. The Hall effect sensor can work with a magnet that can be attached to the rotor 120.

[0056] This rotational sensor 172 and corresponding rotor rotation data can be used in a method of determining the load of the rotor 120 of the centrifugal separator device 100.

[0057] To determine the load of the rotor 120, e.g. the weight of the total content of the rotor 120, which can provide an indication of the load of the accumulated particulate contaminant, e.g. the stage of the dense cake, the method provided herein utilizes a mathematical correlation between the rotor rotation data and the applied fluid pressure, wherein the applied fluid pressure can be controlled by the transient control parameter. In other words, since the load of the rotor 120 is related to the moment of inertia of the rotor 120, the angular acceleration of the rotor 120 will change according to this load, thereby providing a determination of the stage of the dense cake without the need to disassemble the centrifugal separator device 100. To measure the rotor rotation data, the centrifugal separator device 100 can comprise a rotational sensor 172 configured to measure the rotation of the rotor 120 and generate corresponding rotor rotation data. To measure the transient control parameter, the centrifugal separator device 100 can comprise a detector comprising, e.g., a temperature sensor and / or a pressure sensor.

[0058] Accordingly, in some embodiments, there is also provided a centrifugal separator apparatus 110, wherein the rotor rotation data and the transient control parameter for controlling the applied fluid pressure are configured for determining a load of accumulated particulate contaminants separated from the cleaned fluid caused by particulate contaminants deposited on the inner surface of the wall 122. The load of the rotor 120 can be determined based on the rotor rotation data and the transient control parameter. The use (e.g., method) of the rotor rotation data and the transient control parameter for controlling the applied fluid pressure can include providing the transient control parameter for controlling the applied fluid pressure. The method can include the step of generating a change in the rotational frequency of the rotor by modifying the fluid pressure applied to the feed passage in accordance with the transient control parameter. The method can include the step of receiving, from the rotation sensor, rotor rotation data corresponding to the change in the rotational frequency of the rotor. The method can include the step of determining a load of accumulated particulate contaminants separated from the cleaned fluid caused by particulate contaminants deposited on the inner surface of the wall. The load of the rotor 120 can be determined based on the rotor rotation data and the transient control parameter.

[0059] The method can address the above-mentioned disadvantages regarding unnecessary disassembly of the centrifugal separator apparatus and / or inefficiency in separating accumulated particulate contaminants from the cleaned fluid by providing determination of the load of accumulated particulate contaminants in the rotor without requiring disassembly of the centrifugal separator apparatus. Since disassembly of the centrifugal separator apparatus is not required to determine the load of accumulated particulate contaminants in the rotor, resources such as time and manpower can be saved, thereby improving the operational efficiency of the centrifugal separator apparatus. Furthermore, the method is not selective to the type of accumulated particulate contaminants since it only requires a difference in the mass of the rotor load. Thus, the load of all types of accumulated particulate contaminants can be determined by using this method.

[0060] The method utilizes the physical property that when a body is rotating or free to rotate about an axis, a torque must be applied to change its angular momentum. The amount of torque required to cause any given angular acceleration (rate of change of angular velocity) is proportional to the moment of inertia of the body. As the load of accumulated particulate contaminants (i.e., dense mass) accumulates within the rotor, the load of the rotor will increase and the moment of inertia will change. Therefore, it is expected that the torque required to cause angular acceleration will also change.

[0061] In further detail, theoretically, as the load (e.g., load of accumulated particulate contaminants) increases within the rotor, the moment of inertia changes. Therefore, according to the angular acceleration equation (1), the time required to reach a particular angular velocity increases as follows: (1), wherein, α is the angular acceleration, ∂ω is the change in angular velocity, and ∂tis referred to as the time derivative.

[0062] According to the rotational analogy of Newton's second law, torque is related to angular acceleration as shown in equation (2) below: (2), where τ refers to torque, and I is referred to as the moment of inertia.

[0063] In the next stage, the net torque can be determined, which can be the sum of the individual torques. If there is rotational equilibrium, there will be no net torque on the object. There can be separate torques, but they will balance each other due to the equation.

[0064] In this case, the net torque can be calculated as the applied torque τ A which can be related to the rotational frequency of the rotor minus the frictional torques. The frictional torques can include bearing friction τ JB (e.g., friction between the bearings and the rotor), thrust bearing τ TH (e.g., lift of the rotor due to diameter changes at the top and bottom bearings), air resistance on the rotor τ drag , and rotor losses τ loss . Equation (3) below summarizes the calculation of the net torque as follows: (3).

[0065] Using equation (3), equation (2) can then be rewritten as equation (4): (4).

[0066] According to the equation mentioned earlier, the change in the moment of inertia I and thus the change in the load of the rotor has a determinable influence on the angular acceleration α of the rotor, and can be determined, for example, using the differential operator by differentiating equation (4) or by computer implementation and / or its finite approximation.

[0067] The method can therefore rely on the angular acceleration α of the rotor, which can be measured as a change in the rotational frequency of the rotor. This change in the rotational frequency can include modifying the fluid pressure, which can be achieved by providing a transient control parameter. The transient control parameter is therefore defined as a parameter configured to be controlled by an operator, and wherein a change in the transient control parameter can directly or indirectly result in a change in the pressure of the fluid pumped into the feed passage.

[0068] The resulting change in rotational frequency of the rotor can then be measured using a rotational sensor. The rotational sensor can transmit the change in rotational frequency to a processor, such as a microprocessor, in the form of rotor rotation data. After the microprocessor receives the rotor rotation data measured during the change in rotational frequency, the microprocessor can determine a load of accumulated particulate contamination from the fluid based on the load of the rotor by particulate contamination deposited on the inner surface of the wall of the rotor. As described above, the load can be determined based on the rotor rotation data and the transient control parameter.

[0069] According to various embodiments, the transient control parameter can be indicative of a change in operation of the fluid pumping system. In some embodiments, the change in operation of the fluid pumping system can comprise interrupting or stopping the flow of fluid to the feed passage. In other embodiments, the change in operation of the fluid pumping system can comprise starting or accelerating the flow of fluid to the feed passage. In other embodiments, the change in operation of the fluid pumping system can comprise a reversal. For example, the transient control parameter can relate to the starting of an engine (e.g., a motor, e.g., an electric motor) that generates fluid pressure through the fluid pumping system or an increase in engine load of an engine (e.g., a motor, e.g., an electric motor). Alternatively, the transient control parameter can relate to a stop or decrease in engine load of an engine configured to operate fluid pressure through the fluid pumping system. Additionally or alternatively, the transient control parameter can relate to a change in temperature of the fluid (e.g., a clean fluid, e.g., a contaminated fluid), which can generate or be indicative of a change in fluid pressure. Additionally or alternatively, the change in temperature of the fluid can change the viscosity of the fluid, which can generate or be indicative of a change in fluid pressure.

[0070] According to various embodiments, a more specific method can be provided, wherein reference data is used in the calibration. The method can comprise some or all of the method steps of the previously described methods, and can additionally comprise a step wherein the fluid pressure points at different timestamps are comprised by or derived from the transient control parameter, and whereby the rotor rotation data comprises a plurality of data points at different timestamps (e.g., the same different timestamps as the fluid pressure points), and the method can further comprise the steps of matching the plurality of data points or information derived therefrom to the reference data, thereby obtaining a corresponding load factor; and using the corresponding load factor or a value derived therefrom as the load of the rotor, e.g., setting the load of the rotor to the corresponding load factor or a value derived therefrom.

[0071] For example, at different timestamps (e.g., at the same different timestamps as the fluid pressure points), the rotor rotation data can comprise a plurality of data points, e.g., a plurality of data points at different timestamps (e.g., the same different timestamps as the fluid pressure points). t 0 , t 1 , t 2 , …, t nThe fluid pressure point (at which point) may be included in or obtained from transient control parameters, and the rotor rotation data may include data at / with different timestamps (e.g., at time...). t 0 , t 1 , t 2 , …, t n The method then includes matching the multiple data points (or information derived therefrom) with reference data. A corresponding load factor can be determined based on the matching, and the load factor or value derived therefrom can be used to determine the rotor load. The calibration method can be performed based on temperature measurements or on the type of fluid. By using the calibration method described herein to determine the load on the centrifuge unit, frictional torque that may not be considered in the applied torque will not cause any uncertainty because the load determination is based on reference data, not purely mathematically. Therefore, the reference data may include reference data points, which can be obtained, for example, by loading a reference centrifuge unit under controlled conditions and determining the corresponding load factor based on the reference data points.

[0072] In some embodiments, rotor rotation data can describe a curve. For example, in some embodiments, the plurality of data points may include points at / with different timestamps (e.g., at time...). t 0 , t 1 , t 2 , …, t 10, …, t n The method may take 10 or more data points (at the specified locations), and the reference data may include model reference data points obtainable by loading a reference centrifuge under controlled conditions, along with corresponding load factors. The method may then further include extracting coefficients from these multiple data points included in the rotor rotation data as information derived from these data points. This may involve mathematical operations such as fitting curves, determining second derivatives, and / or fitting an nth-degree polynomial (where n is an integer equal to 2 or greater). The matching may then include selecting the model reference data point closest to the extracted coefficients.

[0073] According to various embodiments, another method can be provided in which fluid pressure data points are measured, each having a different timestamp. Thus, the method can include some or all of the method steps of the method as previously described, and can additionally include the step of providing fluid pressure data comprising two or more fluid pressure points each having a different timestamp, and further providing fluid temperature data points each having a different timestamp. In other words, the fluid pressure data can comprise two or more fluid pressure points, where each of the two or more fluid pressure points can have a different timestamp (e.g., at times t 0 , t 1 , t 2 , …, t n ). The fluid pressure points having / at different timestamps can be included in or derived from the transient control parameters. Based on the two or more fluid pressure points obtained at different timestamps, an expected time to achieve a predetermined rotation can be determined. Then, a rotor load can be determined based on a difference between the expected time and a measurement time at which the predetermined rotation will be achieved, where the measurement time at which the predetermined rotation will be achieved can be obtained from rotor rotation data. In embodiments in which the fluid temperature will change during the measurement, the method can additionally include measuring fluid temperature data points each having / at different timestamps (e.g., at times t 0 , t 1 , t 2 , …, t n ), and determining the expected time required to achieve the predetermined rotation based on the fluid pressure points having / at different timestamps and the fluid temperature points having / at different timestamps.

[0074] The predetermined rotation can comprise or consist of a rotational frequency of an operating mode, and the initial state can be a stationary state of zero rotational frequency (e.g., at time t 0 ). Alternatively, the initial state can be an operating mode having an operating rotational frequency different from zero (e.g., at time t n ). The predetermined rotation can comprise or consist of a rotational frequency lower than the operating rotational frequency, and can optionally be zero.

[0075] The method can further comprise determining whether a direction of change of the rotational frequency of the rotor can be indicative of positive acceleration, which can mean start-up of an engine configured to operate on fluid pressure through the fluid pumping system or an increase in engine load. Alternatively, the method can further comprise determining whether a direction of change of the rotational frequency of the rotor can be indicative of negative acceleration, which can mean stoppage of an engine configured to operate on fluid pressure through the fluid pumping system or a decrease in engine load.

[0076] The method can comprise determining an expected rotational frequency that can be expected according to a predetermined time based on fluid pressure points having / at different timestamps and fluid temperature points having / at different timestamps, wherein the fluid pressure points having / at different timestamps can be comprised in or derivable from the transient control parameters; and determining the rotor load based on a difference between the expected rotational frequency and the measured rotational frequency. The measured rotational frequency can be obtained from the rotor rotation data.

[0077] According to another aspect, there can be provided a method of determining a load of a rotor of a centrifugal separator arrangement, such as described herein before. The method can comprise detecting a transient event causing a modification of an applied fluid pressure. The detection can be provided by a detector, which can optionally be comprised in the centrifugal separator arrangement. The detector can be configured to detect a change in a transient parameter. For example, the change in the transient parameter can comprise a change in pressure of the fluid and / or a change in temperature of the fluid. Thus, the detector can comprise or be a pressure sensor and / or a temperature sensor. The change in the transient parameter can comprise a spontaneous (e.g. uncontrolled) change in the transient parameter.

[0078] The method can further comprise detecting a change in a rotational frequency of the rotor resulting from the modification of the fluid pressure applied to the feed passage according to the transient event (e.g. according to the change in the transient parameter). The method can further comprise receiving rotor rotation data corresponding to the change in the rotational frequency of the rotor from a rotation sensor. The method can further comprise determining a load of accumulated particulate contaminants separated from the cleaned fluid of the rotor caused by particulate contaminants deposited on an inner surface of the wall, wherein the load of the rotor can be determined based on the rotor rotation data and the transient parameter.

[0079] According to various embodiments, detecting a transient event causing a modification of the applied fluid pressure can include detecting an event that can be indicative of a spontaneous change or a random change in the operation of the fluid pumping system. Thus, the transient event can include a spontaneous interruption or end of the flow of contaminated fluid to the feed passage. In other embodiments, the change in the operation of the fluid pumping system can include the flow of contaminated fluid to the feed passage being initiated or accelerated. In other embodiments, the change in the operation of the fluid pumping system can include the operation of the fluid pumping system being reversed. For example, the transient event causing a modification of the applied fluid pressure can involve an initiation of an engine or an increase in an engine load of an engine configured to operate the fluid pressure through the fluid pumping system. Alternatively, the transient event causing a modification of the applied fluid pressure can involve an end or a decrease in an engine load of an engine configured to operate the fluid pressure through the fluid pumping system. Additionally or alternatively, the transient event causing a modification of the applied fluid pressure can involve a change in the temperature of the contaminated fluid, which can generate or be indicative of a change in the fluid pressure. Additionally or alternatively, the change in the temperature of the contaminated fluid can change the viscosity of the contaminated fluid, which can generate or be indicative of a change in the fluid pressure.

[0080] According to various embodiments, a method of determining a load of a rotor of a centrifugal separator device can include providing a transient event causing a modification of the applied fluid pressure, as described herein before. According to various embodiments, providing a transient event causing a modification of the applied fluid pressure can include providing an event that can be indicative of a change in the operation of the fluid pumping system, as described herein before.

[0081] In another embodiment, a fluid cleaning system can be provided configured to provide a determination of a load of a rotor of a centrifugal separator device according to a method for determining a load as described herein, the system comprising a centrifugal separator, a rotation sensor, an energy converter, and a processor, such as a microprocessor. The fluid cleaning system can comprise some or all of the elements of the centrifugal separator device 100 as described herein before. Thus, the centrifugal separator device can comprise a rotation sensor 172, which can optionally be an electrical rotation sensor. The centrifugal separator device 100 can further comprise a detector configured to detect a change in a transient parameter or a transient control parameter.

[0082] The microprocessor can be configured to determine a load of accumulated particulate contamination of fluid from the rotor caused by particulate contamination deposited on an inner surface of the wall, wherein the load can be determined based on the rotor rotation data and the transient control parameter.

[0083] According to various embodiments, the fluid cleaning system may also include determining circuitry. This determining circuitry may be configured to determine whether rotor rotation data indicates positive or negative acceleration. If the determining circuitry determines the presence of negative acceleration, it may also be configured to determine the time required to achieve a threshold low rotation (e.g., a stationary state). Alternatively, the determining circuitry may also be configured to determine the time required to achieve a steady state (e.g., a low slope) based on a determined reference rotation and a determined pressure change. In some embodiments, the determining circuitry may be a separate unit separate from the stationary housing and may be included in a microprocessor.

[0084] On the other hand, a method 300 for energy harvesting in a centrifugal separator device is provided. For example... Figure 3 As shown, method 300 may include step 310 of providing a centrifugal separator apparatus as described above herein. Method 300 may include step 320 of positioning an energy converter in a position suitable for collecting non-electrical energy. Method 300 may include step 330 of converting non-electrical energy into electrical energy. Method 300 may include step 340 of supplying electrical energy to a sensor. It is to be understood that method 300 may also include the step of operating the centrifugal separator apparatus to clean contaminated fluids. During such operation, the generated non-electrical energy can be collected by using the energy converter. Method 300 may also include storing the electrical energy in an energy storage device described for the centrifugal separator apparatus for later use.

[0085] On the other hand, a system 400 for energy harvesting in a centrifugal separator apparatus is provided. System 400 may include a centrifugal separator apparatus as described above herein. Figure 4 As illustrated in the illustration, system 400 may therefore include a rotor 420 that generates non-electrical energy 402. During operation of the centrifuge unit, this non-electrical energy 402 may be collected by energy converter 460 and converted into electrical energy 404.

[0086] Features described in the context of an embodiment may be correspondingly applied to the same or similar features in other embodiments. Features described in the context of an embodiment may be correspondingly applied to other embodiments, even if not explicitly described in those other embodiments. Furthermore, additions and / or combinations and / or alternatives as described with respect to features in the context of an embodiment may be correspondingly applied to the same or similar features in other embodiments.

[0087] In the context of various embodiments, the articles “a,” “an,” and “the” used with respect to a feature or element include references to one or more of the features or elements.

[0088] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0089] As used herein, each of the terms “comprise” and “comprising” can include the meaning of “consist of,” “consisting of,” or “consisting essentially of.” For example, “comprising a centrifugal separator device” or “comprising centrifugal separator device” can include the meaning of being a centrifugal separator device, made of a centrifugal separator device, or consisting of a centrifugal separator device.

[0090] Example 1 Example 1 illustrates the effectiveness of the method for determining the load of a rotor of a centrifugal separator device. For example, it illustrates the time difference in accelerating the rotor under different rotor conditions. In short, the rotor speed is relative to the fluid (e.g., oil) pressure and the temperature of that fluid. Thus, the time difference in rotor rotation frequency depending on the applied fluid pressure is compared between i) a full centrifugal separator device; ii) a half-full centrifugal separator device; and iii) an empty centrifugal separator device. From a stationary state, all three centrifugal separator devices are subjected to an applied fluid pressure of 3 bar and 6 bar. The results of the experiment are presented in Figure 5 , Figure 5 is a plot of the rotation frequency (revolutions per minute (rpm)) versus time (seconds). The result is a plot comparing the achieved rotation frequency of each of the three devices at a given time.

[0091] Figure 5 The plot illustrates the graphical correlation of the rotor rotation frequency versus time. Of the three devices described above, the full centrifugal separator device takes the longest time to increase the rotation frequency. The half-full centrifugal separator device takes a medium amount of time to increase the rotation frequency, while the empty centrifugal separator device is the fastest in increasing the rotation frequency. It is further shown that all three centrifugal separator devices accelerate to a given rotation frequency much faster at an applied pressure of 6 bar relative to an applied pressure of 3 bar. The area under each curve can be determined by integrating the equation of the curve and matching the obtained data to a reference table.

[0092] Example 2 As shown in Figure 6 Example 2 illustrates an example of data processing for the method for determining the load of a rotor of a centrifugal separator device. Figure 6 Curve fitting is illustrated in this application as an example of a type of data processing based on measurement points. In Figure 6 , the solid line illustrates the fitted function resulting from these measurement points. In this regard, the measurement points have been processed with a least-squares fitting function applying a 15thorder polynomial, resulting in the solid line as shown in Figure 6 .

Claims

1. A centrifugal separator device (100), the device (100) comprising: - Centrifugal separator, comprising: A fixed housing (110) defines the enclosure; A rotor (120) includes a wall (122) defining an internal volume, wherein the rotor (120) is rotatably mounted in the housing to rotate about a rotation axis; A feed passage (130) for supplying contaminated fluid including particulate contaminants and allowing said contaminated fluid to flow into said internal volume of said rotor (120); and An outlet (140) is provided for releasing the cleaned fluid from the centrifugal separator. The rotor outlet passage (150) is configured to allow the cleaned fluid to flow out in a direction including a tangential component relative to the axis of rotation, thereby causing angular displacement of the rotor (120) when the contaminated fluid is applied via the feed passage (130) at a fluid pressure higher than the fluid pressure threshold, thereby causing the rotor (120) to rotate and generate non-electrical energy during rotation. - An energy converter (160) is located near the rotor (120) and configured to collect the non-electrical energy collected from the centrifugal separator and convert the non-electrical energy into electrical energy; - A sensor (170) configured to acquire parameters associated with the operation of the centrifuge, wherein the sensor (170) includes a processor configured to generate corresponding data; and The sensor (170) is operatively connected to the energy converter (160) to be powered by electrical energy generated by the energy converter (160).

2. The centrifuge separator device (100) according to claim 1, wherein, The non-electrical energy collected from the centrifuge is mechanical energy.

3. The centrifuge device (100) according to claim 2, wherein, The mechanical energy mentioned is vibrational energy.

4. The centrifuge device (100) according to claim 3, wherein, The energy converter (160) includes a piezoelectric transducer (180) configured to withstand mechanical vibration.

5. The centrifuge device (100) according to claim 4, wherein, The energy converter (160) includes an AC-DC rectifier (182) configured to generate a DC voltage.

6. The centrifuge device (100) according to claim 1, wherein, The non-electrical energy collected from the centrifuge is thermal energy.

7. The centrifuge device (100) according to claim 6, wherein, The energy converter (160) includes a thermoelectric generator (190) configured to be subjected to heat sources and radiators.

8. The centrifuge device (100) according to claim 6, wherein, The energy converter (160) includes a DC-DC converter (192) configured to adjust the DC voltage generated by the energy converter (160).

9. The centrifuge device (100) according to claim 5, wherein, The energy converter (160) includes a capacitor (162) arranged to smooth the DC voltage to reduce ripple.

10. The centrifuge device (100) according to claim 1, wherein, The energy converter (160) includes a voltage rectifier (164).

11. The centrifugal separator device (100) according to any one of the preceding claims further includes an energy storage device (166).

12. The centrifuge device (100) according to claim 1, wherein, The sensor (170) is a rotation sensor (172) configured to measure changes in the rotation frequency of the rotor and generate corresponding rotor rotation data.

13. The centrifuge device (100) according to claim 12, wherein, The rotor rotation data and transient control parameters for controlling the applied fluid pressure are configured to determine the load of accumulated particulate contaminants separated from the cleaned fluid due to the particulate contaminants deposited on the inner surface of the wall (122). The load on the rotor (120) is determined based on the rotor rotation data and the transient control parameters.

14. A method (300) for energy harvesting in a centrifuge apparatus according to any one of the preceding claims, wherein, The method includes the following steps: - Provide a centrifugal separator device (310) according to any one of the preceding claims. - Position the energy converter in a location suitable for collecting non-electrical energy (320); - Convert the non-electrical energy into electrical energy (330); and - Provide the electrical energy to the sensor (340).

15. A system (400) for energy harvesting in a centrifuge apparatus according to any one of claims 1 to 13, wherein, The system (400) includes a centrifuge device according to any one of claims 1 to 13, and wherein the energy converter is configured to: Non-electrical energy (402) generated during the rotation of the rotor (420) is collected. Convert the non-electrical energy (402) into electrical energy (404); and The electrical energy is used to power the sensor (470).

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