510results about "Volume/mass flow by dynamic fluid flow effect" patented technology

The utility model relates to the technical field of fluid flow measuring instruments, in particular to a vortex shedding flowmeter which comprises a measuring tube, a generating body embedded in the measuring tube, a sensor arranged on one side of the generating body and a meter head arranged above the sensor. An insertion groove and a fixing groove are sequentially formed in the two sides of the measuring pipe in the direction away from the middle of the measuring pipe respectively, the fixing groove and the insertion groove are each of an annular groove-shaped structure, one end of the fixing groove is communicated with the insertion groove, the other end of the fixing groove is located on the end face of the measuring pipe, and a fixing ring is arranged in the fixing groove in a sleeved mode; the outer diameter of the fixing ring is matched with the groove diameter of the fixing groove, an inner cavity of the fixing ring is of a conical structure, the diameter of the inner cavity of the fixing ring is gradually decreased in the direction close to the inserting groove, a fixing ring made of elastic materials is sleeved with the fixing ring, and the outer structure of the fixing ring is matched with the structure of the inner cavity in the middle of the fixing ring. The vortex shedding flowmeter is good in sealing effect and accurate in measurement result.

The invention relates to the technical field of flow measurement, in particular to a sewage pipeline flow measurement device and method based on dynamic image analysis, and the device comprises a rod body, a control system, a particle release module, a track acquisition module and an image and motion analysis module; the control system is arranged at the top end of the rod body; the track acquisition modules are arranged at the bottom of the rod body; the particle release module is used for storing fluorescent particles and releasing the fluorescent particles into the sewage pipeline to be detected under the control of the control system; the track acquisition module is used for shooting the interior of the sewage pipeline to be detected to obtain an image containing fluorescent particles; the image and motion analysis module is used for analyzing the motion characteristics of the fluorescent particles released in the sewage pipeline to be detected so as to determine the flow of the sewage pipeline to be detected. Thus, the bottom of the device is placed in the sewage pipeline to be detected, the motion characteristics of the fluorescent particles are determined by shooting the tracks of the fluorescent particles, the flow of the sewage pipeline is determined, and the device is efficient, accurate and low in operation difficulty.

An airflow monitoring switch system that includes: a switch having a switch arm that passes through an upper opening of a vacuum line where at least a portion of the switch arm extends through the upper opening of the vacuum line and into an interior of the vacuum line segment; a paddle having a vertical slot running from an uppermost point of the paddle and downwards towards a center point of the paddle; and a first paddle engaging bracket hingedly engaged to the switch arm and the paddle and a second paddle engaging bracket hingedly engaged to the switch arm on an opposite side of the first paddle engaging bracket. The vertical slot has a width that is greater than a width of the switch arm such that when the paddle is in the rotated position the switch arm is at least partially within the vertical slot.

The invention discloses a long-term stable measurement and control method and system for a vortex shedding flowmeter type flow measurement and control device, and relates to the vortex shedding flowmeter type flow measurement and control technology, and the method comprises the steps: collecting a vortex shedding signal generated by a generator, converting the vortex shedding signal into a pulse signal, obtaining the vortex frequency according to the pulse signal, and collecting the pressure information and temperature information of a medium; establishing a temperature correction factor, a pressure correction factor and a corrosion erosion correction factor, and calculating the medium flow according to the calculated vortex shedding flowmeter instrument coefficient; and the calculated medium flow is compared with a set target medium, and if deviation exists, the opening degree of the valve assembly is adjusted. According to the vortex shedding flowmeter, the problem that in the prior art, when the vortex shedding flowmeter operates for a long time, flow measurement and control are not stable due to the influence of temperature, pressure and corrosion on the generating body can be solved.

The utility model relates to the technical field of flow detection, in particular to a turbine flowmeter. The turbine flowmeter comprises a main body, a rotating shaft, a turbine, a detection assembly and a driving assembly, an accommodating cavity for fluid to flow through is formed in the main body; the rotating shaft is located in the containing cavity and arranged in the fluid flowing direction. The rotating shaft is rotationally connected with the body. The turbine is located in the containing cavity and arranged on the rotating shaft. The detection assembly is located in the containing cavity and used for detecting the attack angle of the fluid to the blade so that the turbine flowmeter can determine the fluid flow according to the attack angle. When the turbine flowmeter is used for detection, the influence of a correction or compensation mechanism on the detection efficiency can be eliminated, the detection cost can be reduced, and the detection precision can be improved.

The invention discloses an open channel flow monitoring method and system based on Karman vortex street visual identification and a self-adaptive structure, and relates to the technical field of open channel flow monitoring. The underwater depth of a rod body is automatically adjusted through a telescopic structure, and the formation of a Karman vortex street is stably induced; acquiring a vortex image by adopting a camera and extracting the shedding frequency of the vortex image in real time; and accurately inverting the water velocity and the flow rate by combining a Slodhaar relationship and a learning type model. The open channel flow monitoring method has good water level adaptability, sediment disturbance adaptability and model generalization ability, can realize high-efficiency, low-cost and intelligent open channel flow monitoring under complex field conditions, and provides powerful support for irrigation area water-saving management and control and fine management of water resources.

The invention discloses a self-adaptive vibration suppression vortex shedding flowmeter and a method. The self-adaptive vibration suppression vortex shedding flowmeter comprises a flowmeter shell, a pipe connecting flange, a vortex shedding generator and a piezoelectric sensor, the piezoelectric sensor is embedded into the damping device, the damping device restrains measurement vibration of the piezoelectric sensor, the free end of the piezoelectric sensor is connected with a detection probe, and the detection probe prevents a medium in a flow field from making contact with the root of the detection probe through a joint ring; an inner cavity is formed in the vortex street generating body, and a temperature sensor is integrated in the inner cavity to sense the temperature of fluid flowing through the vortex street generating body in real time; according to the invention, the temperature sensor is integrated in the vortex street generator, so that accurate sensing and real-time compensation of the temperature of a core flow field are realized; multi-stage vibration isolation is constructed through the damping device, the vibration isolation pad, the damping device protection shell and the top base at the same time, and vibration interference is reduced. Due to the optimal design of the detection probe, the durability is improved, and the adverse effect of vibration on signals can be reduced; and the applicability in a complex environment and the reliability of long-term operation are obviously enhanced.

A measuring system for measuring a flow parameter of a fluid flowing in a pipeline includes: a pipe; a bluff body arranged in the pipe and designed to generate vortices in the fluid flowing past the bluff body; a vortex sensor arranged downstream of the bluff body, the vortex sensor designed to produce mechanical vibrations upon being excited by the flowing fluid and to provide a vortex sensor signal and having a magnetostrictive material; a magnetic field detection unit designed to measure a change in a magnetic field resulting from mechanical forces acting on the magnetostrictive material and designed to provide a magnetic field detection signal; and transmitter electronics for analyzing the vortex sensor signal and for analyzing a functionality and / or a plausibility statement regarding the vortex sensor signal provided by the vortex sensor based on the magnetic field detection signal.

The utility model discloses an impact-resistant vortex shedding flowmeter with a tough structure, which relates to the technical field of vortex shedding flowmeters and comprises a vortex shedding flowmeter main body, pipeline impact-resistant components and a lower impact-resistant component, the pipeline impact-resistant components are mounted at two ends of the vortex shedding flowmeter main body, rubber impact-resistant parts are arranged in the pipeline impact-resistant components, and the lower impact-resistant component is mounted in the lower impact-resistant component. The vortex shedding flowmeter comprises a vortex shedding flowmeter body, a lower impact-resistant assembly is installed at the bottom of the vortex shedding flowmeter body, an elastic telescopic piece is arranged in the middle of a rubber impact-resistant piece and comprises a plurality of first rubber elastic rings and second rubber elastic rings, and the size of the first rubber elastic rings is larger than that of the second rubber elastic rings. The vortex shedding flowmeter solves the problems that an existing vortex shedding flowmeter carries out anti-impact operation mainly in the mode that a damping assembly is additionally arranged outside, the structure mainly aims at the influence of surrounding vibration, the effect of weakening vibration transmitted by a pipeline connected with the vortex shedding flowmeter is poor, cost is high, and installation is inconvenient.

The invention provides a turbine flow calculation method based on multiple signals, and belongs to the technical field of turbine flow calculation, and the method comprises the following steps: based on the fact that a measured fluid flows through a turbine flow meter, obtaining multiple signals of the measured fluid by utilizing the turbine flow meter, and calculating the multiple signals of the measured fluid to obtain the multiple signals of the measured fluid; the initial volume flow, temperature and pressure of the measured fluid are obtained; querying the physical property parameter table of the measured fluid, and calculating the density and viscosity of the measured fluid in combination with the temperature and pressure of the measured fluid; setting a calibration test bed and calibration flow, obtaining calibration viscosity, obtaining a correction coefficient through nonlinear fitting and calculation, and constructing a volume flow correction formula; the viscosity of the measured fluid and the initial volume flow rate are substituted into a volume flow rate correction formula, the corrected volume flow rate is obtained, and the mass flow rate of the measured fluid is obtained through calculation in combination with the density of the measured fluid; the problem that an existing turbine flowmeter does not have the density, viscosity and mass flow calculation capacity is solved.

The invention discloses an anti-clogging high-precision liquid flow sensor, and belongs to the technical field of liquid flow sensors, the anti-clogging high-precision liquid flow sensor comprises a shell, a linkage mechanism is arranged in the shell, the linkage mechanism comprises a fixing frame, a bearing, a rotating shaft, a turbine and a signal blade, one end of the rotating shaft is provided with a transmission mechanism, and the other end of the rotating shaft is provided with a transmission shaft; an electromagnet and a flushing mechanism are arranged at the bottom of the shell, the flushing mechanism comprises an electromagnetic valve and a flushing pipe, the flushing pipe is communicated with one end of the electromagnetic valve, the other end of the electromagnetic valve is communicated with a vertical pipe, and the top end of the vertical pipe is communicated with the shell. By introducing an intelligent blockage monitoring mechanism based on mechanical transmission and pressure sensing, the reliability and the pre-maintenance capability of the sensor are remarkably improved, and by integrating a set of on-line high-pressure flushing system triggered by a controller instruction, the self-cleaning function of the interior of a sensor flow channel is achieved; and the long-term cleanness and the measurement precision of the core measurement part are effectively guaranteed.

To provide a measurement and iterative calculation estimation method of fluid velocity with a vortex flowmeter in which the vortex flowmeter can adjust a Strouhal number during uncertain processes, to obtain the accurate fluid velocity to be measured.SOLUTION: A measurement and iterative calculation estimation method of fluid velocity with a vortex flowmeter includes: measuring a differential pressure fluctuation frequency of fluid vortices; obtaining a Nth Strouhal number; obtaining Nth estimated flow velocity based on the Nth Strouhal number and the differential pressure fluctuation frequency of vortices; obtaining a Nth Reynolds number of the fluid based on the Nth estimated flow velocity; obtaining a Reynolds number-Strouhal number correspondence table; obtaining a (N+1)th Strouhal number based on the Reynolds number-Strouhal number correspondence table and the Nth Reynolds number; and obtaining (N+1)th estimated flow velocity based on the (N+1)th Strouhal number and the differential pressure fluctuation frequency of vortices, where N is a positive integer.SELECTED DRAWING: Figure 1

A non-vertical flow meter is provided that includes a chamber comprising an inlet and an outlet, wherein the chamber, the inlet and the outlet are disposed at a non-vertical angle. The non-vertical flow meter also includes a pivoting sensing surface and a load cell. The pivoting sensing surface disposed on an interior surface of the chamber, and the load cell is in operational communication with the pivoting sensing surface and arranged to sense pressure applied to the pivoting sensing surface and output a signal proportional to a flow rate of a material flowing within the chamber.

To provide a flood monitoring device, a flood monitoring system and a flood monitoring method with which it is possible to calculate the water depth and stream speed of rivers with good accuracy, without using expensive sensors.SOLUTION: The present invention comprises: an acquisition unit that acquires a captured image having been captured by an imaging device that captures the image of a buoy on the water surface among buoy-type sensors having a buoy floating on a river and an unwinding mechanism that is connected to the buoy by a connecting line and capable of unwinding and pulling back the connecting line, and that is fixed to the bottom or near the bottom of the river; and a first calculation unit that derives, from the captured image, the horizontal displacement of the buoy from the water surface position in a direction perpendicular to the unwinding mechanism and the submerged state of the buoy, and calculates the water depth and stream speed of the river on the basis of the displacement, the submerged state, and a first relationship of balance of forces and tensions due to the gravity, buoyance and stream acting upon the buoy.SELECTED DRAWING: Figure 2

The invention relates to the technical field of industrial process control and fluid dynamic measurement, and discloses a high-precision liquid flow detection method based on a sensor. The method comprises the following steps: arranging a sensor, initializing a measurement section, receiving an ultrasonic signal, extracting a phase difference updated along with time, executing two-point temperature calibration, converting liquid temperature and correcting sound velocity, and obtaining static propagation time delay and a theoretical phase; constructing a net phase difference, inverting an axial instantaneous flow velocity according to a propagation difference, and applying non-negative and upper bound constraints; collecting pressure fluctuation to estimate a turbulence equivalent speed and superposing the turbulence equivalent speed with the main speed; calculating the volume flow according to the cross section area and accumulating the volume; phase anomaly, temperature rate and pressure peak detection is carried out, and substitution, recalculation and interpolation are adopted respectively; and counting and normalizing the maximum values of the speed and the flow, and outputting the speed, the flow, the accumulated volume and a normalized curve.

The utility model belongs to the field of bridge water level detection, and particularly relates to a bridge water level measuring device. The device comprises a connecting plate connected with external equipment, the connecting plate is connected with a water flow detection assembly, and a water flow counter is arranged at the bottom of a water discharging frame; one side of the drainage frame is fixedly connected with the connecting plate, and the other side of the drainage frame is connected with a water level monitoring assembly; a sliding spring is connected between the sliding block and the inner wall of the connecting frame body, dampers are arranged at the two ends of the sliding spring, corresponding point contacts are arranged on the sliding block and the connecting frame body, and the point contacts are located at the two ends of the sliding spring; all the components are integrated together through the connecting plates, and the device is compact in overall structure, convenient to install, high in impact resistance, complete in auxiliary function, environmentally friendly, capable of saving energy and capable of better meeting the requirement for bridge water level measurement.

A vortex flow meter (100) includes a flowtube (102) configured to receive a flow of process fluid. A shedder bar (118) is disposed within the flowtube (102) and is configured to generate vortices in the flow of process fluid. A vortex sensor (144) is disposed to sense vortices in the flow of process fluid generated by the shedder bar (118). Measurement electronics (202) are operably coupled to the vortex sensor (144) and are configured to detect an analog signal of the vortex sensor (144) and provide a digital indication relative to the analog signal of the vortex sensor (144). A processor (200) is configured to receive the digital indication and calculate velocity of the process fluid flow based on a frequency of the digital indication. The processor (200) is also configured to measure an amplitude of the digital indication and estimate density of the process fluid based on the measured amplitude. The processor (200) is further configured to determine a fluid type based on the measured amplitude and assign a unit of flow corresponding to the calculated velocity to a fluid totalizer corresponding to the detected fluid type.

The invention relates to the technical field of water flow metering equipment, in particular to an impeller box with multiple water inlets and a water meter. The impeller box is provided with an inner cavity and a plurality of water inlets communicated with the inner cavity, a vertical line of an axis extension line of each water inlet passes through the center of the inner cavity, tangent rings of the water inlets are formed by taking the vertical line from the axis extension line of the water inlet to the center of the inner cavity as the radius and the center of the inner cavity as the circle center, and the tangent circle diameters of at least two water inlets are different. A water flow channel formed by the blades of the impeller and the inner cavity is widened from the center to the edge, so that water flow entering the water inlet corresponding to the tangent circle with the small diameter can enter the narrow water flow channel, the water flow is concentrated at the narrow water flow channel, when the water flow is small, the concentrated water flow can generate power enough for pushing the impeller to rotate, and the impeller can be driven to rotate. Therefore, the water meter can meter tiny water flow, and flow metering omission is avoided.

The present invention refers to a respiratory therapy device comprising: a mouthpiece defining a longitudinal axis and having an end port; a housing connected to the mouthpiece and having a top surface, wherein at least a portion of the top surface is longitudinally spaced from the end port and defines a viewing surface adapted to be visible to a user having the end port disposed in a mouth of the user; and a feedback array disposed on the viewing surface, wherein the feedback array extends diagonally across the viewing surface and is curved or curvi-linear.

A system (1) for measuring the flow rate of a fluid is provided, consisting of two modules (100, 200), each with its own housing and detachably connectable to one another. A first module (100) comprises a sensor element (120) for detecting a lifting body (210) for generating measurement signals, an electronic unit (130) for processing the measurement signals, an interface (S) for power supply and communication with a higher-level unit, and a memory (140) containing a list of measurement modes. A second module (200) comprises a measuring section in a measuring tube (220) and the lifting body (210) movably arranged therein. The measuring tube (220) is filled with a fluid that drives the lifting body (210). The first module (100) is configured to uniquely identify the second module (200) in order to select a measurement mode from the list of measurement modes that is suitable for the second module (200). to select.

The invention belongs to the technical field of flow meters, and particularly relates to an intelligent precession vortex flow meter which comprises a measuring pipe body, connecting flanges are connected to the left end and the right end of the measuring pipe body, and a swirler assembly is arranged at an inlet of the measuring pipe body. When the intelligent precession vortex flowmeter is used for detecting the fluid with the low flow speed, the Venturi throat hole of the intelligent precession vortex flowmeter is reduced, the local flow speed of the fluid can be effectively increased under the working condition of the fluid with the low flow speed, the vortex generation strength and stability are enhanced, and the signal amplitude and the signal-to-noise ratio are increased; therefore, the measuring sensitivity, the linearity and the lower limit measuring capacity of the flowmeter in a low-flow-speed area are improved, the applicable flow range is expanded, the flow resistance of fluid in the rotation starting stage can be remarkably reduced by changing the spiral angle of the rotation starting device and reducing the using number of the rotation starting blades, and the rotation strength and the precession stability of the fluid at the low flow speed are enhanced.

The utility model provides a steam vortex shedding flowmeter which comprises a sensor shell, two ends of the sensor shell are suitable for being connected with an external pipeline, and a flat platform in contact with the sensor shell is arranged on the sensor shell; the high-temperature side of the thermoelectric power generation sheet is attached to the flat platform; the heat dissipation assembly is attached to the low-temperature side of the thermoelectric power generation sheet, and the low-temperature side and the high-temperature side of the thermoelectric power generation sheet are opposite to each other; and a power supply output line of the thermoelectric power generation sheet is connected with a power supply input end of the vortex shedding flowmeter converter. The steam vortex shedding flowmeter does not need an external power supply for continuous power supply, and can degrade the maintenance cost and reduce the interference of commercial power frequency.

The application discloses a vortex flowmeter type flow measurement and control device long-term stable measurement and control method and system, relates to vortex flowmeter type flow measurement and control technology, and comprises the following steps: collecting vortex street signals generated by a generator and converting the vortex street signals into pulse signals, so as to obtain vortex frequencies according to the pulse signals; collecting pressure information and temperature information of a medium; establishing a temperature correction factor, a pressure correction factor and a corrosion scouring correction factor; and calculating a medium flow according to a calculated vortex flowmeter instrument coefficient; and comparing the calculated medium flow with a set target medium, and adjusting an opening degree of a valve assembly if there is a deviation. The application can solve the problem that the vortex flowmeter in the prior art is unstable in flow measurement and control due to the influence of temperature, pressure and corrosion on the generator during long-term operation.

Methods and systems for managing characterization of wells using data acquisitions tools are disclosed. The data acquisition tools may be positioned in portions of wells. While positioned in the wells, the data acquisition tools may be measured. The measurements may be ingested into models and may provide, as output, inferred conditions in the portions of the wells. The models may be created using simulation systems. The simulation systems may allow for conditions that may be present in wells to be simulated, and data acquisition tools to be exposed to the simulated conditions. While exposed to the simulated conditions, the data acquisition tools may be measured to establish associations that may be used to infer conditions that may be present in wells.

The invention relates to the technical field of magnetic coupling counters, in particular to an anti-demagnetization magnetic coupling transmission mechanism, a counter and a dry-type watermeter, the anti-demagnetization magnetic coupling transmission mechanism comprises a shell, an impeller, a central gear and a transmission assembly, and the shell is provided with a first cavity and a second cavity; the impeller is arranged in the first cavity, and first magnetic steel is arranged on the end face of the impeller; the sun gear is arranged in the second cavity, second magnetic steel is arranged on the end face of the sun gear, the second magnetic steel and the first magnetic steel are oppositely arranged, and the magnetism of the ends, close to the first magnetic steel, of the second magnetic steel is opposite; the transmission assembly is arranged in the second cavity, the power input end of the transmission assembly is in transmission connection with the center gear, and the transmission assembly is used for transmitting rotation power of the center gear to the power output end. According to the magnetic coupling transmission mechanism, through the first magnetic steel and the second magnetic steel, the demagnetization probability is greatly reduced, magnetic coupling transmission is more reliable, meanwhile, friction resistance of a counter is reduced, the metering grade of a dry type water meter is increased, and the service life of the dry type water meter is prolonged.

The utility model belongs to the technical field of vortex shedding flowmeters, and particularly relates to a vortex shedding flowmeter with a simplified structure, which comprises a base, a connecting pipe is fixedly connected to the top of the base, a telescopic groove is formed in the inner wall of the connecting pipe, grooves are formed in the outer wall of the connecting pipe, spring grooves are formed in the inner walls of the grooves, and bumps are arranged in the grooves. The outer wall of the connecting pipe is in threaded connection with a threaded ring, the bottom of the threaded ring is provided with a positioning ring, the outer wall of the connecting pipe is sleeved with a moving ring, the top of the moving ring is provided with a positioning groove, and the top of the moving ring is provided with a clamping groove. And an extrusion groove is formed in the bottom of the moving ring, sliding blocks are fixedly connected to the inner wall of the moving ring, sliding grooves are formed in the outer wall of the connecting pipe, and the multiple sliding blocks are located in the multiple sliding grooves correspondingly. Under the action of the threaded ring and the movable ring, the meter head main body is convenient and rapid to install, so that the maintenance is convenient.

The invention relates to the technical field of instruments and meters, in particular to a flow meter oil supply test system which comprises a circulating heat conduction piece, a flow meter oil supply test device, a flow meter oil supply test device and a flow meter oil supply test device, the circulating heat conduction piece comprises a cold-hot machine, an inner heat exchange piece and an outer heat exchange piece, and the inner heat exchange piece and the outer heat exchange piece are connected to the cold-hot machine in parallel; the fuel oil part comprises an oil supply part, a flow testing part, a pressure stabilizing part and an oil return part, the oil supply part is arranged outside the inner heat exchange part, so that fuel oil in the oil supply part can be in heat transfer with the inner heat exchange part, and the flow testing part is in through connection with the oil supply part through the outer heat exchange part, so that the fuel oil at the preset temperature is used for carrying out an oil supply test on the turbine flowmeter to be tested; the pressure stabilizing part is in through connection with the flow testing part so as to stabilize the fuel pressure in the test process, and the fuel return part is in through connection with the pressure stabilizing part and the fuel supply part so as to enable the fuel to flow back to the fuel supply part. The test coverage and authenticity can be remarkably improved, the test precision is high, the system structure and reliability are optimized, and the safety and environmental protection performance of the test process are remarkably improved.

The utility model relates to the field of flow detection equipment, in particular to a vortex shedding flowmeter which comprises a pipe body and a vortex generating body, a flow channel is transversely arranged in the pipe body, a first step is arranged on the upper side of the pipe body, a first connecting hole and a first inserting hole matched with the vortex generating body are formed in the first step, and the first inserting hole is vertically arranged. The lower end of the first insertion hole communicates with the flow channel. A connecting part is arranged at the upper end of the vortex generating body, and a second connecting hole is formed in the connecting part; the vortex generating body is inserted into the first inserting hole and extends downwards into the flow channel, the connecting part abuts against the upper side of the first step, and the first connecting hole and the second connecting hole are fixedly connected through a screw. According to the vortex shedding flowmeter, the first step is arranged on the upper side of the pipe body, the vortex generating body is inserted into the first inserting hole and fixedly connected with the first step through the screw, a through hole does not need to be formed in the lower side of the pipe body, water flow is prevented from overflowing from the through hole in the lower side, and the sealing performance of the vortex shedding flowmeter is improved.

The measuring system is used for sensing two temporally variable primary measured variables (x1, x2) and / or secondary measured variables (y1) derived therefrom. It comprises a measuring electronics, an active sensor element (C1), a passive sensor element (R1) and an electrical connection line. The sensor element (C1) generates a voltage dependent on x1, while the sensor element (R1) varies its resistance dependent on x2. Within a defined interval (t1), measurement electronics drive a measurement current through R1 and interrupt the current before (t2) and after (t3) the interval, as a result of rising and falling current edges occurring in transition intervals (t4, t5). Furthermore, the measuring electronics temporarily sense and analyse the voltages (u1, u2), and the measurement is effected in a specific time interval in order to allow a fault-free and accurate evaluation.