Turbine flow meter
By integrating a control winding and programmable frequency divider into turbine flowmeters, the flow meter's operability can be remotely checked, addressing the lack of simulated testing and ensuring long-term conversion stability, enhancing their use in automatic control systems.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- AKTSIONERNOE OBSHCHESTVO NAUCHNO PROIZVODSTVENNOE OBEDINENIE IZMERITELNOJ TEKHNIKI
- Filing Date
- 2026-01-26
- Publication Date
- 2026-07-07
AI Technical Summary
Existing turbine flowmeters with inductive sensors lack the capability for a simulated performance test within an operating facility and have insufficient long-term stability of the frequency-to-voltage conversion factor due to changes in ambient temperature and aging components.
Incorporating an additional control winding into the inductive sensor and a programmable frequency divider into the measuring unit, along with a calibrated pulse generator, D-triggers, and a reference voltage source, allows for a remote check of the flow meter's operability and stability of the frequency-to-voltage conversion factor.
Enables a remote, non-disassembly check of the flow meter's functionality and ensures high stability of the conversion factor throughout its service life, allowing for reliable operation within automatic control systems.
Smart Images
Figure 00000014_ABST
Abstract
Description
[0001] The invention relates to turbine flow meters designed for operation as part of automatic (operating without human intervention) control systems, in which increased requirements are imposed on flow measurement devices for speed and metrological reliability.
[0002] A turbine flowmeter is known from the prior art. Its operating principle is based on the conversion of the translational motion of a fluid into the rotational motion of a moving element - a turbine (Boshnyak L.L., Vyzov L.N. Tachometric flowmeters. Mashinostroenie Publishing House, 1968, pp. 105-106). The inertia of the turbine is tenths or even hundredths of a second, therefore turbine flowmeters are used to measure instantaneous flow in aviation, marine and rocket technology products, the operation of which is accompanied by high-speed processes. A turbine flowmeter consists of a flow transducer and a measuring unit. The flow transducer includes a circular cross-section measuring channel, a turbine mounted in the channel on sliding supports with the ability to rotate, and a tachometric transducer located directly above the trajectory of the blades.Inductive sensors, which contain a coil with a magnet and winding, are primarily used as tachometric transducers in turbine flowmeters. These sensors have a simple and reliable design and, as the turbine rotates, generate a harmonic signal whose frequency is proportional to the flow rate and can be measured with high accuracy. The signal from the inductive sensor is fed to a measuring unit, which can be located either on the flow meter or remotely. The measuring unit converts the frequency of the tachometric transducer signal into an output value proportional to the flow rate, which is fed to the input of the corresponding data channel of the control system.
[0003] During operation of the flow meter as part of the automatic control system, its operability must be periodically checked (according to clause 14 of GOST R 27.102-2021, operability is the state of an object in which it is capable of performing the specified functions, maintaining the values of the main parameters established by the normative and technical documentation), and this check must be carried out without dismantling the flow meter and human intervention. For this purpose, the automated control system (of which the automatic system is a special case) has the necessary capabilities: according to clause 4.2.1, lists 1 and 3, GOST 24.104-2023, the automated control system must collect, process and analyze information (signals, etc.) on the state of the controlled object and transmit control actions (signals, etc.) for execution.The primary method for non-disassembly flow meter performance testing is simulation. This involves a control system command to generate a test signal from the flow transducer, corresponding to a known measured flow rate. The test signal is converted by the measuring unit into an output value, which is in turn converted by the control system into a flow rate value. The latter is compared with a reference value stored in the control system's memory: if the measured and reference flow rates differ by an amount not exceeding the flow meter's error, the flow meter is considered functional. Otherwise, the measurement result is adjusted accordingly, or a conclusion is made that the flow meter is faulty.Considering that the integrity of the communication line between the tachometer converter and the measuring unit must also be verified during a performance check, to fully verify the flowmeter's electrical circuit, the test signal must be generated by the tachometer converter itself. This capability is not provided in existing turbine flowmeters with inductive sensors, limiting their scope of application. The objective of the proposed technical solution is to expand the scope of application of turbine flowmeters with inductive sensors, specifically, to enable their use in automatic control systems.
[0004] The closest prototype to the claimed device is a high-speed turbine flowmeter with an inductive sensor and a frequency-to-voltage pulse converter. The flowmeter comprises a flow transducer and a measuring unit. The flow transducer comprises a circular measuring channel, a turbine with ferromagnetic blades mounted in the channel on sliding supports capable of rotation, and an inductive sensor with a permanent magnet and winding located in the channel directly above the blade trajectory. The measuring unit contains a series-connected amplifier-limiter, a dosing device, which is a generator of standard (calibrated) pulses, and an integrating link connected to the winding (Tachometric flowmeters. Boshnyak L.L., Vyzov L.N., Mechanical Engineering Publishing House, 1968, pp. 179, 185-186, Fig. 86a, 93, 94). The flowmeter operates as follows.A fluid (liquid or gas) passing through the measuring channel rotates a turbine. The moving blades of the turbine induce a sinusoidal signal in the working winding of the inductive sensor, which is converted by the amplifier-limiter into rectangular pulses. These pulses are differentiated to form short pulses that control the metering device, which, with each incoming pulse, generates a calibrated pulse with a constant amount of electricity (charge). The metering device consists of a resistor and capacitor connected in series, recharged at the signal frequency using a switch. The voltage at the output of the integrator (the flow meter output) is proportional to the average current value of the metering device over the signal period, i.e., the frequency.The response time of such a flowmeter is determined by the time constant of the integrating element, typically based on an RC circuit, and can be as short as tenths of a second at an inductive sensor signal frequency of 100-1000 Hz. Therefore, it can be used to measure rapidly varying flow rates and is characterized by the simplicity and reliability of its electrical circuit.
[0005] A disadvantage of the described turbine flowmeter is the lack of the ability to conduct a simulated performance test within the operating facility. Furthermore, it has insufficient long-term stability of the frequency-to-voltage conversion factor, due to changes in the parameters of the capacitor and resistor of the metering device due to changes in ambient temperature and the aging processes occurring within these components. However, to ensure the required performance test efficiency, it is necessary not only to generate a test signal at the output of the inductive sensor but also to ensure the stability of the frequency-to-voltage conversion factor throughout the entire service life of the flowmeter.
[0006] The technical problem solved by the proposed invention consists of providing, as part of an automatic control system, a remote check of the operability of a turbine flow meter with an inductive sensor and a frequency-to-voltage pulse converter, including a check of the integrity of the inductive sensor - measuring unit circuit.
[0007] The said problem is solved due to the fact that in a known turbine flow meter, including a flow converter with a measuring channel of circular cross-section, a turbine with ferromagnetic blades installed in the channel in sliding supports with the possibility of rotation and an inductive sensor with a permanent magnet and a working winding installed in the channel directly above the trajectory of the blades and a measuring unit including a series-connected amplifier-limiter, the input of which is connected to the working winding, a calibrated pulse generator and an integrating link, ACCORDING TO THE INVENTION, an additional control winding is introduced into the inductive sensor, and a programmable frequency divider and a key controlled by an external signal are introduced into the measuring unit, wherein the calibrated pulse generator is made of a reference frequency generator, a counter with an arbitrary conversion factor,first and second D-triggers with dynamic control and a reference voltage source, wherein the output of the limiting amplifier is connected to the clock input of the first trigger, the information input of which is connected to the power source, and the direct output is connected to the information input of the second trigger, wherein the counting input of the counter and the clock input of the second trigger are connected to the generator, and the input for setting the counter to the initial state is connected to the inverse output of the first trigger, wherein the output of the counter is connected to the input for setting the first trigger to the initial state, and the inverse output of the first trigger is connected to the input for setting the counter to the initial state, wherein the direct output of the second trigger is connected to the integrating link, wherein the control winding is placed on the magnet and is located directly above the working winding, wherein the control winding is connected through a key to the output of a programmable frequency divider, the input of which is connected to the generator, wherein the frequency F, Гthe reference frequency generator is (3F ВП ) / , where F ВП - the frequency of the inductive sensor signal at the upper measurement limit and - relative error of the flow meter, where the conversion factor of the meter with an arbitrary conversion factor is 0.9F Г / F ВП , while the division factor of the programmable frequency divider is F Г / F ВП .
[0008] The essence of the invention is explained by the drawings, which show: Fig. 1 - a block diagram of the proposed turbine flow meter, Fig. 2 - timing diagrams of signals at the outputs of individual elements of the block diagram.
[0009] The turbine flowmeter includes a flow converter 1 and a measuring unit 2. The flow converter 1 includes a measuring channel 3 of a circular cross-section, a turbine 6 with ferromagnetic blades installed in the channel 3 in sliding supports 4, 5 with the possibility of rotation, an induction sensor 7 placed in the channel 3 directly above the trajectory of the blades with a magnet 8, a working winding 9 and a control winding 10 located directly above it. The measuring unit 2 includes an amplifier-limiter 11, a calibrated pulse generator 12, an integrating element 13, a programmable frequency divider 14 and a key 15. The calibrated pulse generator 12 consists of a reference frequency generator 16, a counter 17 with an arbitrary conversion factor, the first 18 and second 19 D-triggers with dynamic control and a reference voltage source 20.The output of the integrating link 13 is connected to the input of the information channel of the control system, and the control input of the switch 15 is connected to the output of the control channel of the control system. Frequency F. Г signal of generator 16 is , where F ВП - the signal frequency of the inductive sensor 5 at the upper limit of flow measurement Q ВП And - relative error of the flow meter, the conversion factor of the counter 17 is 0.9F Г / F ВП , and the division factor of frequency divider 14 is F Г / F ВП
[0010] The turbine flow meter has two operating modes: "Measuring" and "Control." In "Measuring" mode, the contacts of switch 15 are open; in "Control" mode, they are closed. Switch 15 closes when a control signal (e.g., DC voltage) is applied to its control input from the control system.
[0011] In the "Measurement" mode, the flow meter operates as follows. The medium (liquid or gas) flowing through the measuring channel 3 at a flow rate Q causes the turbine 6 mounted in the sliding supports 4, 5 to rotate. As the turbine 6 rotates, its blades periodically pass near the induction sensor 7, crossing the magnetic field created by the magnet 8. In this case, the magnetic flux coupled to the working winding 9 periodically changes due to the distortions introduced by the ferromagnetic blades, as a result of which an electromotive force (signal) of a sinusoidal shape (Fig. 2a) with a frequency
[0012]
[0013] From the working winding 9, the signal is fed to the input of the limiting amplifier 11. The limiting amplifier 11 can be implemented using the 1401UD2A operational amplifier as a series connection of a non-inverting amplifier and a non-inverting Schmitt trigger. From the output of the limiting amplifier 11, the signal, converted into rectangular pulses (Fig. 2b), is fed to the clock input of the trigger 18. Triggers 18 and 19 can be implemented using the 564TM2 microcircuit, which contains two D-type triggers with dynamic control. The information input D of flip-flop 18 is set to the logical "1" state, and its clock input C is connected to the output of limiting amplifier 11. The voltage from the direct output of flip-flop 18 is fed to the information input D of flip-flop 19, and the voltage from the inverse output of flip-flop 18 is fed to the forced reset input R of counter 17. Pulses from the output of reference frequency generator 16 are fed simultaneously to the clock input C of flip-flop 19 and to the counting input T of counter 17.Generator 16 can be built on a 564LA7 microcircuit, which contains four 2NAND logic elements, using a highly stable quartz resonator as the frequency-setting element. Before the pulse edge from the output of limiting amplifier 11 arrives at the clock input of trigger 18, a logical "0" from the output of counter 17 is applied to its input R, and a logical "1" from the inverse output of trigger 18 is applied to the R input of counter 17, and pulse counting does not begin. At the edge of the output pulse of limiting amplifier 11, the direct output of trigger 18 is set to the logical "1" state, and the inverse input is set to the logical "0" state. At the pulse edge of generator 16, the direct output of trigger 19 is set to the logical "1" state, and counter 17 begins counting the pulses of generator 14.Counter 17 with an arbitrary conversion factor and a number of digits equal to 10 can be implemented on two 564IE10 microcircuits, each of which consists of two summing four-digit binary counter-dividers. The output of the last digit of the previous counter is connected to the counting input of the next one, where the counting input of the first counter is connected to the output of generator 16. The outputs of all ten digits are connected to the contacts of single-pole switches, the second contacts of which are connected to the cathodes of diodes, the anodes of which are connected to each other (output of counter 17) and connected to the R input for resetting the trigger 18 and, through a current-limiting resistor, to the power source. The number of pulses at which the counting ends (Fig. 2c) is set by closing the contacts of the switches of the corresponding digits and is equal to the conversion factor K. П counter 17, which according to the invention is:
[0014]
[0015] where F Г - the frequency of the signal of the generator 16, which is, according to the invention,
[0016]
[0017] When condition (3) is met, the quantization error when setting the frequency of the reference signal is 3 times less than the error of the flow meter, i.e., in accordance with the 3-sigma rule, it can be neglected.
[0018] During the counting process, the logic level "0" is maintained at the R input of trigger 18. At the end of the counting, the outputs of the bits corresponding to the number K П, are set to the logical "1" state. Trigger 18 is reset, its direct output is set to logical "0", which is fed to the information input of trigger 19. At the inverse output of trigger 18, logical "1" is set, which is fed to the R input of resetting counter 17. In this case, the outputs of the bits of counter 17 are set to the logical "0" state and pulse counting stops. Upon arrival of the pulse edge from the output of generator 16 at the clock input of trigger 19, its direct output is set to the logical "0" state. The pulse generated at the direct output of trigger 19 has a calibrated duration T equal to K П (conversion factor) to the periods of the signal of the reference generator 16:
[0019]
[0020] With the arrival of the edge of the next pulse from the output of the limiting amplifier 11, the cycle is repeated. As a result, a sequence of rectangular pulses calibrated in duration with a repetition rate F is generated at the direct output of the trigger 19 (Fig. 2d). When condition (2) is met, the duration of these pulses T at maximum flow does not exceed 90% of the signal period of the tachometric converter 1 / F ВПThis ensures linearity of the frequency-to-voltage conversion over the entire frequency range F. Triggers 18 and 19 are powered by reference voltage source 20 (in which, for example, a precision Zener diode D818E can be used as a stabilizing element), so the pulses generated at the direct output of trigger 19 have a calibrated amplitude. Thus, the pulses arriving at the input of integrating element 13 have a calibrated volt-second area (the product of the amplitude and the duration).The sequence of calibrated pulses of frequency F is converted by the integrating element 13 (which can be a two-element RC low-pass filter and a normalizing amplifier based on the operational amplifier 1401UD2A) into a constant voltage U, proportional to the ratio of the duration of the calibrated pulses T to the period of the tachometric converter signal, equal to 1 / F (the reciprocal of the pulse duty cycle) and the voltage at the upper limit of measurements U. ОП :
[0021]
[0022] Voltage U comes from the output of the integrating link 13 to the input of the information channel of the control system, which calculates the measured flow rate Q in accordance with the formula resulting from (5):
[0023]
[0024] In "Control" mode, a simulated check of the flow meter's functionality is performed. For this purpose, a test signal is generated by programmable frequency divider 14. The programmable frequency divider can be built using a 564IE15 programmable counter and a frequency divider by 2 connected to its output, which can be implemented using a D-trigger. The sequence of rectangular pulses with frequency F Гand a duty cycle of 2 from the output of generator 16 is fed to the counting input T of the programmable counter 564IE15 connected to it. The mode selection input L of the programmable counter 564IE15 is set to the logical "0" state, the inputs of the module M shaper (Ka, Kv, Ks) are set to the logical "1" state, and each of the division ratio setting inputs J1...J16 is connected to a current-limiting resistor and to a contact of a single-pole switch. The second contacts of the resistors are connected to the power source, and the second contacts of the switches are connected to the common bus. The division ratio is set in binary code by setting logical "0" or "1" at the inputs J1...J16 of the divider 14 by closing / opening the contacts of the switches and is, according to the invention,
[0025]
[0026] From the output of the programmable counter 564IE15, a sequence of rectangular pulses with a repetition frequency F Г / TO Д and duration 1 / F Гis fed to the input of a D-trigger, which divides the pulse repetition rate by two. The pulse sequence obtained at the output of the D-trigger (which is the output of programmable frequency divider 14) has a repetition rate of F К =F ВП / 2 and a duty cycle of 2, simulating the sensor signal and serving as a test signal, is fed to the input of switch 15 (which can be a RES80 relay), to the control input of which a constant voltage is supplied from the control system. From the output of switch 15 closed in the "Control" mode, the test signal is fed to the control winding 10. Since the control winding 10 is placed on a magnet and is located directly above the working winding 9, an alternating signal of the same frequency is induced in the latter, which is fed to the input of the limiting amplifier 11. After the reference signal has passed through the corresponding circuits of the flowmeter's electrical circuit, a constant voltage U is formed at the output of the integrating element 13 in accordance with (5).K :
[0027]
[0028] This voltage is converted by the control system into measured flow rate according to (6):
[0029]
[0030] Thus, if the flow meter is normal, the measured flow value in the "Control" mode is equal to the control value Q ВП / 2, stored in the memory of the control system, with a tolerance within the flow meter error Otherwise, the control system generates a flow meter malfunction signal.
[0031] The technical result achieved by implementing the claimed technical solution consists in providing the possibility of conducting a remote (without requiring dismantling the flow meter and the participation of the operator) check of the operability of a turbine flow meter with an inductive sensor and a frequency-voltage pulse converter directly at the operating facility, and the check covers all circuits of the flow meter, including the working winding of the inductive sensor.
[0032] The specified technical result is achieved due to:
[0033] - execution of the calibrated pulse generator 12 from the reference frequency generator 16, the counter with an arbitrary conversion factor 17, the first 18 and second 19 D-triggers with dynamic control, and the reference voltage source 20. In this case, high stability of the volt-second area of the pulses subject to averaging is ensured due to the fact that their amplitude is equal to the highly stable reference voltage, and the duration is an integer number of periods of the signal of the highly stable quartz generator 16, and this number is specified by the condition (2), which ensures the normal operation of the calibrated pulse generator at the maximum pulse repetition frequency corresponding to the maximum flow rate. High stability of the volt-second area of the pulses predetermines high long-term stability of the "frequency - voltage" conversion factor, providing the possibility of carrying out a simulation test of the operability of the flowmeter during its full service life;
[0034] - formation of a highly stable test signal with frequency F from the signal of the reference frequency generator 16 (which is part of the calibrated pulse generator 12) using the newly introduced programmable frequency divider 14 ВП / 2, corresponding to the flow rate value, exactly equal according to condition (7) to half the upper limit of measurements Q ВП / 2. The frequency of generator 16 is selected based on condition (3) - in this case, the error in setting the frequency of the reference signal is 3 times less than the error of the flow meter, i.e., it is negligibly small;
[0035] - introduction of switch 15 into the flow meter, which closes in the “Control” mode when a control action (for example, voltage) is applied to it from the control system and connects the output of the programmable frequency divider 14 with the newly introduced control winding 10, ensuring that a test signal is applied to it;
[0036] - location of the control winding 10 on the magnet directly above the working winding 9, which ensures the formation of a test signal in the working winding due to electromagnetic coupling with the control winding;
[0037] - using a flow meter as part of an automated control system, which is equipped with the hardware and software necessary to generate a control signal that closes switch 15 when implementing the "Control" mode, converting the output voltage of the flow meter into a flow value, storing the control flow value Q in memory ВП / 2, comparing it with the flow rate value measured in the “Control” mode and issuing a signal about the operability / non-operability of the flow meter based on the comparison results.
Claims
A turbine flow meter comprising a flow converter with a circular cross-section measuring channel, a turbine with ferromagnetic blades mounted in the channel in sliding supports with the possibility of rotation and an inductive sensor with a permanent magnet and a working winding mounted in the channel directly above the trajectory of the blades, and a measuring unit comprising a series-connected amplifier-limiter, the input of which is connected to the working winding, a calibrated pulse generator and an integrating link, characterized in that an additional control winding is introduced into the inductive sensor, and a programmable frequency divider and a key controlled by an external signal are introduced into the measuring unit, wherein the calibrated pulse generator is made of a reference frequency generator, a counter with an arbitrary conversion factor, first and second D-triggers with dynamic control and a reference voltage source,wherein the output of the limiting amplifier is connected to the clock input of the first trigger, the information input of which is connected to a power source, and the direct output is connected to the information input of the second trigger, wherein the counting input of the counter and the clock input of the second trigger are connected to the generator, and the input for setting the counter to the initial state is connected to the inverse output of the first trigger, wherein the output of the counter is connected to the input for setting the first trigger to the initial state, and the inverse output of the first trigger is connected to the input for setting the counter to the initial state, wherein the direct output of the second trigger is connected to the integrating link, wherein the control winding is placed on the magnet and is located directly above the working winding, wherein the control winding is connected through a key to the output of the frequency divider, the input of which is connected to the generator, wherein the frequency of the generator F, Г is (3F) ВП ) / , where F ВП- the frequency of the inductive sensor signal at the upper limit of flow measurement and - relative error of the flow meter, where the conversion factor of the meter with an arbitrary conversion factor is 0.9F Г / F ВП , while the division coefficient of the programmable frequency divider is F Г / F ВП .