Flow metering device

Abstract

The utility model relates to the technical field of flow metering, in particular to a flow metering device which comprises a main body, a rotating assembly, a driving mechanism, a first rotating speed detection element and a control unit, a containing cavity is formed in the main body, the rotating assembly is rotatably arranged in the containing cavity, the driving mechanism is arranged on the main body, and the first rotating speed detection element is arranged on the main body. The first rotating speed detection element is used for detecting the rotating speed of the rotating assembly, and the control unit is electrically connected with the driving mechanism and the first rotating speed detection element and is configured to control the driving mechanism to drive the rotating assembly to rotate when the fluid flow is smaller than nominal flow; the flow meter can solve the problem that a traditional flow meter does not rotate under the condition of micro flow due to friction force, and the micro flow cannot be detected; according to the utility model, the zero value of the flowmeter can be determined, the problem of zero drift caused by factors such as bearing wear is avoided, the accuracy of the flowmeter in a long-time use process is ensured, and reliable precision correction is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to flow measurement technical field, concretely relates to a flow measurement device. BACKGROUND

[0002] Flow meter is a device for measuring the flow of fluid in the pipeline, which is various in type and different in measuring principle. Some flow meters completely or partially rely on the flow power of fluid to push some components (such as rotating turbine or gear, etc.), so as to drive the measuring mechanism of the flow meter. Among them, the flow meter completely relying on fluid power is volumetric flow meter, turbine flow meter and float flow meter; the flow meter partially relying on fluid power is differential pressure flow meter, vortex flow meter and thermal mass flow meter. In the actual measurement process, the flow meter completely or partially relying on fluid power as mentioned above cannot detect the micro flow when measuring the micro flow, because the micro flow of fluid cannot push some components. In addition, after using the aforementioned flow meter for a period of time, the friction force increases due to factors such as wear, which requires a larger flow of fluid to push some components, resulting in poor range and detection accuracy of the flow meter.

[0003] The following takes turbine flow meter as an example to further illustrate the deficiencies of the prior art. Turbine flow meter, as a typical speed type flow measurement instrument, is widely used in petrochemical industry, energy measurement, industrial process control and other fields due to its simple structure, high precision and good repeatability. Its working principle is based on the driving of fluid flow to rotate turbine rotor, and the linear relationship between rotor speed and flow rate is detected to realize flow measurement. When using the traditional single rotor turbine flow meter, the speed of turbine is proportional to the flow rate of fluid under certain flow range and fluid conditions, that is, the greater the flow rate, the faster the speed of turbine. Therefore, the flow rate of fluid can be indirectly obtained by measuring the speed of turbine. When fluid impacts turbine blades, turbine starts to rotate. The proportional relationship between the speed of turbine and the flow rate of fluid enables turbine flow meter to convert the flow rate of fluid into the rotating speed of turbine. This conversion process is based on the principle of fluid dynamics, that is, the kinetic energy of fluid is converted into mechanical energy of turbine. However, in reality, due to the effect of friction force on turbine rotor, the impact force of small water flow is not enough to drive turbine rotor to rotate, which leads to the inability to detect the flow of small water flow and the leakage problem, affecting the precision of turbine flow meter, and unable to determine the zero point value of rotor turbine and the zero point drift of flow meter caused by bearing wear. In addition, turbine flow meter is an electronic detection instrument, which needs long-term external power supply. Therefore, there is an urgent need in the field to solve the demand for self-power supply of turbine flow meter without affecting high-precision measurement, and to estimate the service life of turbine flow meter and correct the precision. SUMMARY

[0004] The utility model aims at solving one of the above technical problems in prior art at least to some extent.

[0005] In order to realize the above-mentioned purpose, the utility model provides a flow metering device, including:

[0006] The main body is internally formed with a containing cavity;

[0007] The rotating assembly is rotatably arranged in the containing cavity;

[0008] The driving mechanism is arranged on the main body;

[0009] The first rotating speed detection element is used for detecting the rotating speed of the rotating assembly; and

[0010] The control unit is electrically connected with the driving mechanism and the first rotating speed detection element respectively, and is configured to control the driving mechanism to drive the rotating assembly to rotate when the fluid flow is less than the nominal flow.

[0011] Preferably, the rotating assembly is one of a turbine rotor, an elliptical double rotor, a waist wheel double rotor or a rotary piston.

[0012] Preferably, the driving mechanism includes at least one set of electromagnetic coils, the electromagnetic coils are arranged around the outside of the rotating assembly, at least one magnet is arranged on the rotating assembly, and the electromagnetic coils are configured to be able to drive the rotating assembly to rotate through the magnet after being energized.

[0013] Preferably, the flow metering device further includes an energy storage unit, and the control unit is configured to control the electromagnetic coils to switch to a power generation mode and store electrical energy into the energy storage unit when the fluid flow reaches the nominal flow.

[0014] Preferably, the energy storage unit is used to power the control unit.

[0015] Preferably, the flow metering device further includes an alarm unit, and the control unit is configured to perform overload alarm through the alarm unit when the fluid flow reaches an overload flow, and perform leakage alarm through the alarm unit when the fluid flow is above a starting flow for a certain time.

[0016] Preferably, the flow metering device further includes a secondary rotor and a second rotating speed detection element, the secondary rotor is arranged to be driven to rotate by the fluid flowing through the rotating assembly, and the second rotating speed detection element is used to detect the rotating speed of the secondary rotor.

[0017] Preferably, the sub-rotors are provided with a plurality of sub-rotors, and the plurality of sub-rotors are configured to be driven to rotate by fluid flowing through a previous sub-rotor in a flow direction of the fluid.

[0018] By the above technical solution, when the fluid flow is less than the nominal flow, the control unit controls the driving mechanism to drive the rotating assembly to rotate, then the first rotating speed detection element is used to detect the rotating speed of the rotating assembly, and then the standard flow detection table is used to determine the actual flow value. The technical solution provided by the utility model can overcome the problem that the traditional flowmeter cannot detect the small flow due to the existence of friction force, and can determine the zero point value of the flowmeter, avoid the zero point drift problem caused by bearing wear and other factors, ensure the accuracy of the flowmeter during long-term use, and realize reliable precision correction. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic view of a flowmeter provided by the utility model;

[0020] Figure 2 is a schematic view of a rotating assembly in the form of an elliptical double rotor provided by the utility model;

[0021] Figure 3 is a structural schematic view of a double-rotor turbine vertical installation provided by the utility model;

[0022] Figure 4 is a principle schematic view of a standard flow detection table provided by the utility model;

[0023] Figure 5 is a working flow chart of a double-rotor turbine flowmeter provided by the utility model;

[0024] Figure 6 is a measurement comparison chart of a double-rotor turbine flowmeter and a traditional flowmeter provided by the utility model;

[0025] MARKING OF DRAWINGS

[0026] 100, main body; 101, containing cavity; 102, fluid inlet; 103, fluid outlet; 200, main rotor; 210, first rotating speed detection element; 220, magnet; 300, control unit; 400, electromagnetic coil; 500, energy storage unit; 600, sub-rotor; 610, second rotating speed detection element. DETAILED DESCRIPTION

[0027] The specific embodiments of the utility model are described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model.

[0028] In order to facilitate the understanding of the flow metering device provided by the utility model embodiment, first, some terms related to the utility model embodiment are explained.

[0029] Starting flow (Qs): the minimum flow value at which the flow meter can start continuous and stable measurement and recording, that is, the threshold flow of starting measurement. If the fluid flow is lower than Qs, the flow meter may not be able to detect or work intermittently; the starting flow Qs is usually slightly higher than the minimum flow Q1.

[0030] Minimum flow (Q1): the minimum flow value that the flow meter can accurately measure, below which the indication error of the flow meter may exceed the allowable range, and through which the low-end measurement capability of the flow meter is represented; the minimum flow Q1 is usually combined with the transitional flow Q2 to divide the error limit interval (low and high regions) of the flow meter.

[0031] Transitional flow (Q2 or Qt): the critical flow value that divides the high and low flow intervals of the flow meter, and the error allowable range is different in different flow intervals.

[0032] Nominal flow (Q3 or Qn): the regular use flow specified in the design of the flow meter, representing its typical working condition; it is usually lower than the maximum flow but higher than the transitional flow Q2.

[0033] Overload flow (Q4): the maximum flow that the flow meter can withstand for a short time, and exceeding this value may cause permanent damage or error out of control; the value is the upper limit of the flow range, and is usually 1.6-2 times the nominal flow Qn.

[0034] In combination Figure 1 As shown in the figure, the utility model provides a kind of flow metering device, including main body 100, rotating component, drive mechanism, first rotating speed detection element 210 and control unit 300;The inside of the main body 100 is formed with containing cavity 101;The rotating component is rotatably arranged in the containing cavity 101;The drive mechanism is arranged on the main body 100;The first rotating speed detection element 210 is used to detect the rotating speed of the rotating component;The control unit 300 is electrically connected with the drive mechanism, the first rotating speed detection element 210 respectively, and is configured as when fluid flow is less than nominal flow, the drive mechanism is controlled to drive the rotating component rotation.

[0035] The utility model discloses a flow metering device, which comprises a main body 100, a fluid inlet 102 and a fluid outlet 103.

[0036] According to the technical scheme of the utility model, when the fluid flow is less than the nominal flow, the driving mechanism is controlled to drive the rotating assembly to rotate by the control unit 300, then the rotating speed of the rotating assembly is detected by the first rotating speed detection element 210, and then the standard flow detection table is detected to determine the actual flow value. The technical scheme provided by the utility model can overcome the problem that the traditional flow meter does not rotate at a small flow due to the existence of friction, so that the small flow cannot be detected. Moreover, the technical scheme provided by the utility model can determine the zero point value of the flow meter and the zero point drift problem caused by bearing wear and other factors, ensure the accuracy of the flow meter during long-term use, and realize reliable precision correction.

[0037] In some embodiments of the utility model, the rotating assembly can be one of a turbine rotor, an elliptical double rotor, a waist wheel double rotor or a rotary piston. The turbine rotor is a form that rotates around its own axis by driving the impeller of the turbine by fluid, and the rotating speed of the turbine rotor is proportional to the flow rate. The elliptical double rotor forms a closed chamber by two intermeshing elliptical gears, drives the elliptical gear to rotate by fluid, and measures the volume by rotating speed (such as shown in the figure). Figure 2 The waist wheel double rotor is suitable for high-viscosity fluid by alternating rotation of two waist wheel rotors. The rotary piston is measured by volume change of the chamber by setting an eccentric rotating piston in the accommodating cavity.

[0038] It should be noted that although the utility model will mainly take the turbine rotor as an example of the rotating assembly in the following text, the rotating assembly in the utility model can also be an elliptical double rotor, a waist wheel double rotor or a rotary piston, which is a type of flow meter that relies on fluid power to realize the measurement mechanism.

[0039] In the utility model, the driving mechanism can be any appropriate structure as long as it can provide power when the fluid is not enough to drive the rotating assembly to rotate, so that the rotating assembly can rotate. In some embodiments of the utility model, the driving mechanism comprises at least one set of electromagnetic coils 400, the electromagnetic coils 400 are arranged around the outside of the rotating assembly, at least one magnet 220 is arranged on the rotating assembly, and the electromagnetic coils 400 are configured to drive the rotating assembly to rotate by the magnet 220 after being energized.

[0040] It can be understood that in order to improve the driving effect, the magnet 220 can be provided with a plurality of magnets 220 arranged in a ring array in the circumferential direction of the rotating assembly.

[0041] In some embodiments, the flow metering device further comprises an energy storage unit 500, and the control unit 300 is configured to control the electromagnetic coil 400 to switch to a power generation mode and store electrical energy into the energy storage unit 500 when the fluid flow reaches the nominal flow. By the above setting, the kinetic energy of the fluid can be fully utilized; in addition, when the electromagnetic coil 400 is switched to the power generation mode, the high-speed rotation of the bearing can also be damped, the friction of the bearing is reduced, and the service life of the bearing is improved.

[0042] In some embodiments, the energy storage unit 500 is used to power the control unit 300, that is, the structural design of the utility model can realize the demand of self-power supply while ensuring the service life of the equipment. It can be understood that the energy storage unit 500 can specifically include a rectifier and voltage stabilizing circuit and a storage battery, which can store the alternating current generated by the electromagnetic coil 400 into the storage battery after rectification and voltage stabilization, so as to realize power supply to the control unit 300 and the like, and then realize self-power supply of the flow metering device. In the utility model, the magnet 220 arranged on the rotating assembly can be selected as a neodymium iron boron strong magnetic material, which can generate a stable motion magnetic field when following the rotating assembly, and under the action of the motion magnetic field, the electromagnetic coil 400 arranged around the rotating assembly generates an induced current.

[0043] In some embodiments, the flow metering device further comprises an alarm unit, and the control unit 300 is configured to perform overload alarm through the alarm unit when the fluid flow reaches the overload flow, and perform leakage alarm through the alarm unit when the fluid flow exceeds a certain time at the starting flow. It can be understood that the alarm unit can be any appropriate prior art, such as a wireless communication alarm mode.

[0044] In some embodiments, the flow metering device further comprises a secondary rotor 600 and a second rotating speed detection element 610, the secondary rotor 600 is arranged to be driven to rotate by the fluid flowing through the rotating assembly, and the second rotating speed detection element 610 is used to detect the rotating speed of the secondary rotor 600.

[0045] In a specific embodiment of the utility model, the rotating assembly and the secondary rotor 600 are both arranged as turbine rotors, such as Figure 1As shown, the rotating component is the primary rotor 200 arranged upstream of the secondary rotor 600, by arranging the primary rotor 200 and the secondary rotor 600 to be capable of being closely coupled, the primary rotor 200 and the secondary rotor 600 rotate in opposite or same directions, the fluid flowing out of the primary rotor 200 affects the inlet incident angle of the secondary rotor 600, thereby hydraulically coupling the two rotors, more specifically, the fluid vortex condition of the primary rotor 200 has an opposite effect on the secondary rotor 600, if the primary rotor 200 slows down due to the vortex effect, the secondary rotor 600 will accelerate at the same percentage, and vice versa, if the primary rotor 200 accelerates, the secondary rotor 600 will slow down.

[0046] The turbine flowmeter with double rotors provided by the utility model provides power for the primary rotor 200 through the driving mechanism, and drives the secondary rotor 600 to rotate around its own axis through the hydraulic coupling mode, provides a measurement result that cannot be realized by the traditional single-rotor structure, effectively expands the flow measurement range of the turbine flowmeter, and significantly improves the range ratio, for example, can be improved to 1:400, 1:800 or even higher, and such a wide flow measurement range eliminates the need for a more expensive straight pipe section system.

[0047] In some embodiments, the secondary rotor 600 is provided in plurality, and the plurality of secondary rotors 600 are configured to be driven to rotate by the fluid flowing through the previous secondary rotor 600 in the flow direction of the fluid. Through the above arrangement, the measurement accuracy of the flowmeter can be further improved.

[0048] It should be noted that in the above embodiments of the utility model, the number of secondary rotors 600 can be two, three or four. In theory, the number of secondary rotors 600 is not limited, but too many secondary rotors 600 will increase the cost of the device, and therefore is not the optimal solution. Based on the cost and measurement accuracy, one secondary rotor 600 is arranged, that is, the double-rotor scheme is the optimal solution.

[0049] In the utility model, the primary rotor 200 and the secondary rotor 600 can be installed in the accommodating cavity 101 of the main body 100 in any appropriate form, for example, the primary rotor 200 and the secondary rotor 600 are vertically installed (as shown in Figure 3 ), or are horizontally installed (as shown in Figure 1 ).

[0050] In the utility model, the primary rotor 200 and the secondary rotor 600 can be helical rotors or rotor wings; the primary rotor 200 and the secondary rotor 600 can be in the form of bearing connection (including ceramic bearing) and top rod connection (including magnetic suspension connection).

[0051] In the utility model, first rotation speed detection element 210 and second rotation speed detection element 610 are used to detect the rotation speed of rotating assembly (main rotor 200) and auxiliary rotor 600 respectively.The utility model does not make special limitation to the kind of first rotation speed detection element 210 and second rotation speed detection element 610, for example, can select the hall sensor commonly used in the field.

[0052] The utility model further provides a kind of method for flow measurement based on above flow measurement device.

[0053] Specifically, in the flow measurement device of only rotor assembly, the method includes: when fluid flow is less than nominal flow, the control unit 300 controls the driving mechanism to drive the rotating assembly to rotate, the rotation speed of the rotating assembly is detected by the first rotation speed detection element 210, then the standard flow detection platform is marked to determine actual flow value;When fluid flow reaches nominal flow, the control unit 300 detects the rotation speed of the rotating assembly by the first rotation speed detection element 210, then the standard flow detection platform is marked to determine actual flow value.

[0054] In the flow measurement device including rotor assembly and auxiliary rotor 600, the method includes: when fluid flow is less than nominal flow, the control unit 300 controls the driving mechanism to drive the rotating assembly to rotate, utilizes fluid coupling to drive the auxiliary rotor 600 to rotate, the rotation speed of the rotating assembly and the auxiliary rotor 600 is detected by the first rotation speed detection element 210 and the second rotation speed detection element 610 respectively, then the standard flow detection platform is marked to determine actual flow value;When fluid flow reaches nominal flow, the control unit 300 detects the rotation speed of the rotating assembly and the auxiliary rotor 600 by the first rotation speed detection element 210 and the second rotation speed detection element 610 respectively, then the standard flow detection platform is marked to determine actual flow value.

[0055] The following is with the scheme of double rotor (rotor assembly is main rotor 200, and main rotor 200 and auxiliary rotor 600 are turbine rotors) as an example, to make further explanation and instruction to the flow measurement device and measurement method provided by the utility model.

[0056] (1) zero correction:

[0057] When fluid is in static state, the control unit 300 controls electromagnetic coil 400 to be electrified, electromagnetic coil 400 acts on magnet 220 on main rotor 200, drives main rotor 200 to rotate around its own axis, further drives auxiliary rotor 600 to rotate through fluid coupling, the rotation speed of main rotor 200 and auxiliary rotor 600 is detected by the first rotation speed detection element 210 and the second rotation speed detection element 610 respectively, so that the zero point of double rotor turbine flowmeter can be calculated.

[0058] In addition, by comparing with the standard time, the bearing wear coefficient of the main rotor 200 and the secondary rotor 600 is determined. Exemplarily, the detection is carried out after a certain time interval, if the time is reduced, it indicates that the bearing corresponding to the rotor has wear phenomenon, by bringing the wear coefficient into the flow formula, that is, subtracting the wear coefficient can ensure the flow measurement accuracy. Through the above structure design and measurement method of the utility model, the service life of the turbine flowmeter can be estimated and the flow accuracy can be self-corrected. From another angle, based on the above structure design and measurement method of the utility model, the service life of the turbine flowmeter can be improved, and the preliminary estimation can reach several decades or even longer.

[0059] (2) Start-up flow detection:

[0060] The start-up flow detection is the core of the flow detection sensitivity, and the stable start-up flow is to ensure that the double-rotor turbine flowmeter can detect the flow value at the initial flow, and ensure the integrity of the flow data.

[0061] When the double-rotor turbine flowmeter provided by the utility model starts to flow, the control unit 300 controls the electromagnetic coil 400 to be powered, the electromagnetic coil 400 acts on the magnet 220 on the main rotor 200, drives the main rotor 200 to rotate around its own axis, further drives the secondary rotor 600 to rotate through fluid coupling, the rotation frequency and one rotation time of the secondary rotor 600 are determined through the corresponding detection of the rotation speed of the main rotor 200 and the secondary rotor 600 by the first rotation speed detection element 210 and the second rotation speed detection element 610, and then the standard time and frequency at the start-up flow are determined and the standard flow detection table is marked, the rotation frequency of the main rotor 200 and the rotation frequency of the secondary rotor 600 are determined under the driving of the main rotor 200, the frequency difference of the two is calculated, the regression model is fitted, and the start-up flow value, that is, the actual start-up flow value or the alarm leakage value of the double-rotor turbine flowmeter is obtained.

[0062] (3) Small flow detection:

[0063] For the convenience of subsequent description, the small flow here is defined as Q1.

[0064] The small flow detection is the initial flow value of the flow detection (that is, the trade measurement starts to charge), and the stable small flow is to ensure that the double-rotor turbine flowmeter can detect the flow value at the small flow, and ensure the integrity of the flow data.

[0065] The double-rotor turbine flowmeter provided by the utility model can control the energization of the electromagnetic coil 400 through the control unit 300 when the flow is small, the magnet 220 on the main rotor 200 is acted on by the electromagnetic coil 400, the main rotor 200 is driven to rotate around its own axis, the secondary rotor 600 is further driven to rotate through fluid coupling, the rotation speed of the main rotor 200 and the secondary rotor 600 is detected through the first rotation speed detection element 210 and the second rotation speed detection element 610, the rotation frequency and one rotation time of the secondary rotor 600 are determined, the standard time and frequency when the flow is small are further determined, the standard flow detection platform is marked, the rotation frequency of the main rotor 200 and the rotation frequency of the secondary rotor 600 under the driving of the main rotor 200 are determined, the frequency difference of the two is calculated, a regression model is fitted, and the small flow value, i.e. the small flow value or the leakage alarm value of the actual double-rotor turbine flowmeter, is obtained.

[0066] (4) boundary flow detection:

[0067] For the convenience of subsequent description, the boundary flow defined here is Q2, for example, Q1:Q2=1:1.6, at this time, the flow precision is allowed to be twice as large as the precision of the nominal flow.

[0068] The boundary flow detection is the boundary flow precision value (i.e. how much trade measurement charges) of the flow detection, and the stable boundary flow can ensure that the double-rotor turbine flowmeter can detect the flow precision value when the flow is at the boundary flow, and ensure the integrity of the flow data.

[0069] The double-rotor turbine flowmeter provided by the utility model can control the energization of the electromagnetic coil 400 through the control unit 300 when the flow is at the boundary flow, the magnet 220 on the main rotor 200 is acted on by the electromagnetic coil 400, the main rotor 200 is driven to rotate around its own axis, the secondary rotor 600 is further driven to rotate through fluid coupling, the rotation speed of the main rotor 200 and the secondary rotor 600 is detected through the first rotation speed detection element 210 and the second rotation speed detection element 610, the rotation frequency and one rotation time of the secondary rotor 600 are determined, the standard time and frequency when the flow is at the boundary flow are further determined, the standard flow detection platform is marked, the rotation frequency of the main rotor 200 and the rotation frequency of the secondary rotor 600 under the driving of the main rotor 200 are determined, the frequency difference of the two is calculated, a regression model is fitted, and the boundary flow value, i.e. the boundary flow precision value of the actual double-rotor turbine flowmeter, is obtained.

[0070] (5) nominal flow detection:

[0071] For the convenience of subsequent description, the nominal flow defined here is Q3, and the precision of the nominal flow represents the precision of the double-rotor turbine flowmeter.

[0072] The nominal flow detection is the flow detection nominal flow precision value (i.e. trade measurement charges), and the stable nominal flow is to ensure that the double-rotor turbine flowmeter can detect the flow precision value of the double-rotor turbine flowmeter at the nominal flow, and ensure the integrity of the flow data.

[0073] The double-rotor turbine flowmeter provided by the utility model is used for driving the main rotor 200 by the fluid flowing through the main body 100, cutting the electromagnetic coil 400 by the magnet 220 arranged on the main rotor 200 while rotating, generating electromotive force in the electromagnetic coil 400 (i.e. realizing power generation), detecting the rotating speeds of the main rotor 200 and the auxiliary rotor 600 by the first rotating speed detection element 210 and the second rotating speed detection element 610, obtaining the rotating frequency and one-week rotating time of the main rotor 200 and the auxiliary rotor 600, further determining the standard time and frequency at the nominal flow and the standard flow detection table, determining the rotating frequency of the main rotor 200 and the rotating frequency of the auxiliary rotor 600, calculating the frequency difference of the two, fitting the regression model, and obtaining the nominal flow value, i.e. the nominal flow precision value of the actual double-rotor turbine flowmeter.

[0074] (6) Overload flow detection

[0075] For the convenience of subsequent description, the overload flow defined here is Q4, and the precision of the overload flow represents the overload precision of the double-rotor turbine flowmeter.

[0076] The detection of the overload flow is the flow detection overload flow precision value (i.e. overload flow, which needs to be alarmed); and the stable overload flow is to ensure that the double-rotor turbine flowmeter can detect the flow precision value of the double-rotor turbine flowmeter at the overload flow, and the value higher than the value needs to be alarmed.

[0077] The double-rotor turbine flowmeter provided by the utility model is used for driving the main rotor 200 by the fluid flowing through the main body 100, cutting the electromagnetic coil 400 by the magnet 220 arranged on the main rotor 200 while rotating, generating electromotive force in the electromagnetic coil 400 (i.e. realizing power generation), detecting the rotating speeds of the main rotor 200 and the auxiliary rotor 600 by the first rotating speed detection element 210 and the second rotating speed detection element 610, obtaining the rotating frequency and one-week rotating time of the main rotor 200 and the auxiliary rotor 600, further determining the standard time and frequency at the nominal flow and the standard flow detection table, determining the rotating frequency of the main rotor 200 and the rotating frequency of the auxiliary rotor 600, calculating the frequency difference of the two, fitting the regression model, and obtaining the nominal flow value, i.e. the nominal flow precision value of the actual double-rotor turbine flowmeter.

[0078] Table 1 is a segmented correction coefficient lookup table of the double-rotor turbine flowmeter provided by the utility model.

[0079] Table 1:

[0080]

[0081]

[0082] In the utility model, when the turbine flowmeter is in measuring each area, it is opposite to the standard flow detection platform, and the correction coefficient Kcorr is obtained by looking up the table; the actual flow calculation is: Q 实际 = Q 测量 * Kcoor; wherein, Q 实际 is the actual flow of the double-rotor turbine flowmeter, Q 测量 is the flow detected by the standard flow detection platform, and Kcorr is the correction coefficient.

[0083] As Figure 4 It is a kind of principle schematic diagram of standard flow detection platform provided by the utility model, and it is specifically a kind of active volumetric flow calibration device, including control system, grating sensor, ball screw, piston, water tank, heater, filter and control cabinet, the active volumetric flow calibration device is pushed through the reciprocating motion of piston Fluid through flowmeter, and the position of ball screw is monitored in real time by grating sensor, to realize accurate control and measurement of fluid flow, complete active volumetric flow calibration of double-rotor turbine flowmeter. Figure 4 As shown in the figure, in the active volumetric flow calibration device, control system is used to control the operation of the whole calibration device, grating sensor is used to measure the position and movement of ball screw, to realize accurate control of flow, ball screw is connected with piston, and fluid is pushed by the reciprocating motion of piston, to realize flow control;Water tank is used to store fluid, provides the fluid required by calibration device, heater is arranged in water tank, is used to heat fluid, ensures that fluid reaches the required temperature during measurement;Filter is used to filter impurities in fluid, to protect subsequent equipment. Control cabinet contains control circuit and electronic equipment for controlling and managing the operation of the whole calibration device.

[0084] As Figure 5 It is the working flow chart of double-rotor turbine flowmeter provided by the utility model.

[0085] In specific work, control unit 300 (the utility model embodiment adopts MCU (micro control unit)) realizes wake-up (for example, is woken up once every 15s) by built-in timer, after wake-up, MCU detects the speed signal of main rotor 200 and auxiliary rotor 600 by first speed detection element 210 and second speed detection element 610.

[0086] When there is no signal, the MCU controls the power supply to the electromagnetic coil 400, drives the main rotor 200 to rotate through the magnet 220, drives the secondary rotor 600 to rotate through fluid coupling, then detects the rotation speed of the main rotor 200 and the secondary rotor 600, judges the flow area (zero point area, starting area, small flow area or boundary flow area), then looks up the table corresponding to the area, calculates the actual flow value; then stops the power supply to the electromagnetic coil 400, stops driving the main rotor 200 to rotate through the magnet 220, and then detects the rotation speed of the main rotor 200 and the secondary rotor 600 again, if there is, continue to judge the flow area; if not, the MCU enters sleep, and restarts according to the timer setting.

[0087] When there is a signal, it means that the main rotor 200 has been driven by the fluid to rotate around its own axis, at this time, the rotation speed signals of the main rotor 200 and the secondary rotor 600 are directly detected through the first rotation speed detection element 210 and the second rotation speed detection element 610, then the flow area (nominal flow area or overload flow area) is judged, then the table corresponding to the area is looked up, the actual flow value is calculated, and the power generation mode is started or the alarm is started according to the area; then the rotation speed of the main rotor 200 and the secondary rotor 600 is detected again, if there is, the flow area is continuously judged; if not, the MCU enters sleep, and restarts according to the timer setting.

[0088] As Figure 6 is a measurement comparison chart of a double-rotor turbine flowmeter and a traditional flowmeter provided by the utility model, Figure 6 Four different range ratios of the prior art are given in the table, which are R=50, R=80, R=160 and R=200; the parameter comparison of the four prior arts and the double-rotor turbine flowmeter provided by the utility model is shown in the following table 2.

[0089] Table 2:

[0090]

[0091] The double-rotor turbine flowmeter provided by the utility model can also realize zero point correction, and the starting flow is 0.001m 3 / h.

[0092] Combined Figure 6 with the data in table 2, it can be seen that the double-rotor turbine flowmeter provided by the utility model has good detection effect on the part below the nominal flow, overcomes the defects that the traditional turbine flowmeter cannot correct zero point and detect small flow, and further the double-rotor turbine flowmeter provided by the utility model can effectively increase the range range and significantly improve the range ratio.

[0093] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited thereto. Within the technical concept of the present application, the technical solution of the present application can be subjected to various simple modifications. In order to avoid unnecessary repetition, the present application will not be described again for various possible combination manners. However, these simple modifications and combinations should also be regarded as the disclosed content of the present application, and all belong to the protection scope of the present application.

Claims

1. A flow metering device, characterized by The application relates to a flow metering device, which comprises: a main body (100), an accommodating cavity (101) being formed in the inside of the main body (100); a rotating assembly, which is rotatably arranged in the accommodating cavity (101); a driving mechanism, which is arranged on the main body (100); a first rotating speed detection element (210), which is used for detecting the rotating speed of the rotating assembly; and a control unit (300), which is electrically connected with the driving mechanism and the first rotating speed detection element (210) respectively, and is configured to control the driving mechanism to drive the rotating assembly to rotate when the fluid flow is less than the nominal flow.

2. The flow metering device of claim 1, wherein, The rotating assembly is one of a turbine rotor, an elliptical double rotor, a waist wheel double rotor or a rotary piston.

3. The flow metering device of claim 1, wherein, The driving mechanism comprises at least one set of electromagnetic coils (400), which are arranged around the outside of the rotating assembly, at least one magnet (220) is arranged on the rotating assembly, and the electromagnetic coils (400) are configured to drive the rotating assembly to rotate through the magnet (220) after being electrified.

4. The flow metering device of claim 3, wherein, The flow metering device further comprises an energy storage unit (500), and the control unit (300) is configured to control the electromagnetic coils (400) to switch to a power generation mode and store electric energy into the energy storage unit (500) when the fluid flow reaches the nominal flow.

5. The flow metering device of claim 4, wherein, The energy storage unit (500) is used for supplying power for the control unit (300).

6. The flow metering device of claim 1, wherein, The flow metering device further comprises an alarm unit, and the control unit (300) is configured to perform overload alarm through the alarm unit when the fluid flow reaches the overload flow, and perform leakage alarm through the alarm unit when the fluid flow exceeds the starting flow for a certain time.

7. The flow metering device according to any one of claims 1-6, characterized in that, The flow metering device further comprises a secondary rotor (600) and a second rotating speed detection element (610), the secondary rotor (600) is arranged to be driven to rotate by the fluid flowing through the rotating assembly, and the second rotating speed detection element (610) is used for detecting the rotating speed of the secondary rotor (600).

8. The flow metering device of claim 7, wherein, A plurality of secondary rotors (600) are arranged, and the secondary rotors (600) are configured to be driven to rotate by the fluid flowing through the previous secondary rotor (600) in the flowing direction of the fluid.

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