RU2625539C1 - Inductive sensor of tachometric liquid metre - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: inductive sensor of the tachometric liquid metre contains a sensing element in the form of an inductance coil (1) located in the tube (2), which is plugged on one side at its end. The end of the tube (2) is located near the target (4) fixed to the turbine (3). The inductance coil (1) is connected by a cable (5) to the tuned-circuit capacitor (6), connected to the microcontroller (7). The turbine (3) is rotatably mounted in the bearing assemblies (8) located in the guides (9) of the liquid flow metre body (10). The tuned-circuit capacitor (6) is connected to the microcontroller (7) located on the electronic board of the inductive sensor device (11), which is hermetically fixed to the body of the liquid flow metre (10). The turbine (3) consists of two sections: a section with blades (12) and a cylindrical section (13) with the target (4). The target (4) is made of a flat ferromagnetic material, curved and fixed along the radius of the cylindrical part of the turbine (13). A flat pattern of the target (in plan) is made in the form of three identical rectangles (14) connected by two thin bridges of different lengths (15) and (16).

EFFECT: simplified design of the inductive sensor and operation method, increased reliability of the device on the whole.

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Description

The invention relates to instrumentation, and in particular to meters for measuring the flow rate of the amount of water flowing in pipes with a passage diameter greater than 40 mm

A device for measuring fluid flow according to the patent for the invention of the Russian Federation: RU 2238524 C2 dated 10.20.2004, IPC G01F 1/075, G01F 15/075 - [1], comprising a housing having an inlet and an outlet, an impeller with at least , with one magnet, a counting device with a liquid crystal indicator and a reed switch interacting with the impeller magnet and connected to a computing device including an integrator connected to the liquid crystal indicator, characterized in that it is additionally equipped with a thermal relay with a liquid temperature sensor and a back sensors of the actuation steps, and the integrator is equipped with several autonomous integration channels, the number of which is equal to the number of actuation stages of the thermal relay, with each channel of the integrator connected to its corresponding liquid crystal indicator.

A disadvantage of the known device [1] is the use of an impeller with a tangential fluid supply to it, which does not allow the use of this technical solution as meters for measuring the flow rate of the amount of water flowing in pipes with a passage diameter of more than 40 mm, since impeller meters cannot provide sufficient accuracy for measuring fluid volume.

A device for a meter for measuring fluid flow with axial flow inlet to a turbine (in pipes with a passage diameter of more than 40 mm) according to the patent of Ukraine: UA 73416 C2 of 04/15/2005, IPC G01F 1/10 - [2], comprising a casing, a turbine installed in it with a magnet mounted on its blades, on the surface of the casing there is a computing device for the rotation of the turbine made in the form of an electronic summing device, a reed switch located in the plane of rotation of the magnet is connected to the cup, while the magnet is located in the middle blade impeller, and at all other impeller blades mounted weights whose weight is equal to the weight of the magnet and they are also located in the middle of the impeller blades.

The main disadvantage of the device [2] is the use of a magnet and weighting materials in the blades of the turbine for its alignment (balancing), which significantly reduces the manufacturability of the turbine and its reliability.

The device of a turbine water flow meter according to the patent for the invention of the Russian Federation: RU 2528614 C2 dated 09/20/2014, IPC G01F 1/10 - [3], solves the problem of eliminating the disadvantages of the device [2] for placing a magnet and weighting agent (add-on) on the cylindrical part of the turbine, and the placement of the sensing element - reed switch in the tube at the cylindrical part of the turbine. The turbine water flow meter [3] contains a housing in which a turbine with a permanent magnet and an accessory is mounted on the shaft in the transverse walls, an electronic device that sums up the speed of the turbine, to which a reed switch is connected, a permanent magnet is installed on the end of the turbine, and a reed switch is installed in the hole of the transverse wall case made of non-magnetic material, opposite the magnet and connected to the input of the summing device, made in the form of an electric pulse counter, operating from a short circuit of its input, in particular and, by closing the reed switch contacts by a magnetic field of the permanent magnet.

A fluid meter according to the patent for the invention of the Russian Federation is also known: RU 2029915 C1 dated 02.27.1995, IPC G01F 1/10 - [4], containing a turbine located in the measuring channel of the pipeline, the casing of which has a closed cavity, a gearbox and a counting mechanism mounted on the pipeline with the possibility of interaction with the gearbox, in the housing of the turbine is made at least one through hole communicating the measuring channel with a closed cavity, in one of the parts of which is placed the gearbox. The part of the cavity of the turbine housing in which the gearbox is located can be communicated with the measuring channel through a filter. The cavity of the turbine housing may be filled with liquid. The through hole can be made in the form of a tubular channel connecting the measuring channel with the axial part of the cavity of the turbine housing.

The disadvantage of devices [3] and [4], as well as devices [1] and [2] is that a reed switch is used as a sensitive element in these devices, which significantly reduces the reliability and durability of the device, and also requires the creation of protection against external magnetic fields (for example, a strong permanent magnet). Using a magnet mounted on an impeller or impeller requires careful balancing. In addition, when using a magnet-reed switch pair, it is not possible to determine the direction of rotation of the impeller or impeller.

A known turbine flowmeter according to the patent for the invention of the Russian Federation: RU 2084828 C1 from 07.20.1997, IPC G01F 1/10 - [5], which use an inductor (electromagnet) interacting with a flat ferromagnetic material mounted (fixed) on the turbine. The turbine flowmeter [5], comprises a housing, an inlet and outlet cowlings, an impeller mounted on the shaft of the impeller and a chamber with thrust bearings and seals located in the outlet cowl cavity, the impeller and shaft being hollow to form a closed cavity filled with air, with a volume of providing zero buoyancy of the impeller and shaft in the medium being measured, and an electromagnet is placed in the cavity of the inlet fairing to interact with a plate of magnetic material mounted on the impeller, and the casing the stalk and shaft are made of non-magnetic material. The flow meter can be equipped with a shaft axial displacement transducer installed in the output cowl, connected to an electromagnet through a current regulator.

The disadvantage of a turbine flow meter [5] is the complexity of its design, and, therefore, its low reliability. However, in the device [5], an electromagnet and a plate of ferromagnetic material are used not as a rotation sensor, but to unload the turbine. In addition, the patent does not describe the principle (method) of operation of the turbine rotation recorder, which does not allow the well-known technical solution to be applied in practice.

The prototype of the claimed technical solution for using an inductor as a sensitive element to determine the speed and direction of rotation of the turbine, on which targets (cores) of flat ferromagnetic material are mounted, is a "Rotation Sensor for a Water Meter" according to German patent: DE 19725806 (A1) from 28.01 .1999, IPC G01D 5/20, G01F 1/075, G01F 1/115 - [6]. Moreover, in the device [6], two inductors are used to determine the direction of rotation, each of which is connected to its capacitor and, accordingly, to form two oscillatory circuits that are connected to the microcontroller. A target mounted on a turbine has at least two sectors with different ferromagnetic properties. In two oscillatory circuits, respectively, the oscillations are excited by pulses from the microcontroller. The signals from the oscillatory circuits after a fixed time after the excitation of oscillations (hereinafter - ΔT) are fed to the built-in comparator, where it is compared with the level of the digital-to-analog converter (DAC). After comparison, the conclusion is made about the presence or absence of a ferromagnetic target (sector) near the sensing element - the inductor, and by the order in which the inductance coils belonging to the two oscillatory circuits overlap, the direction of rotation is determined and the complete complete revolutions of the turbine are calculated. Further, knowing the volume value corresponding to one revolution of the impeller, the volume of leaking water in m ^{3 is} calculated.

The disadvantage of the prototype device [6] is the need to use two sensitive elements — inductors to determine the direction of rotation of the turbine, which complicates its design and reduces its reliability. In addition, when installing the prototype on a standard turbine liquid flow meter, two technological holes must be made to install two inductors (two sensing elements).

The technical result consists in a significant simplification of the design of the inductive sensor and the method of its operation, as well as improving the reliability of the device as a whole.

The technical result is achieved (the essence of the invention) is achieved by the fact that the inductive sensor of the tachometric fluid meter contains a sensing element in the form of an inductor located in the tube muffled on one side at its end, the tube end is located near the target mounted on the turbine, made of flat ferromagnetic material, the inductor is connected by a cable to the capacitor of the oscillatory circuit connected to the microcontroller, the impeller is mounted for rotation in the bearing assemblies of the guides of the body of the fluid flow meter, the oscillator circuit capacitor is connected to a microcontroller located on the electronic circuit board of the inductive sensor device, which is hermetically mounted on the housing of the fluid flow meter, while the turbine consists of two sections: a section with blades and a cylindrical section with a target, moreover, the target is curved and fixed along the radius of the cylindrical part of the turbine, and a flat scan of the target (in plan) is made in the form of three identical rectangles with connected by two thin jumpers of different lengths.

Signs of the restrictive part of the formula "inductive sensor of a tachometric fluid meter containing a sensing element in the form of an inductor located in a tube muffled on one side at its end, the end of the tube is located near a target mounted on a turbine made of flat ferromagnetic material, the inductor is connected by a cable to a condenser of an oscillating circuit connected to a microcontroller, the impeller is mounted for rotation in the bearing assemblies of the rails the housing of the flow meter, the capacitor of the oscillatory circuit is connected to a microcontroller located on the electronic circuit board of the inductive sensor device, which is hermetically mounted on the housing of the flow meter ”describes common features with the prototype [6] installed on the fluid meter.

An introduction to the claims of the essential feature: “a turbine consists of two sections: a section with blades and a cylindrical section with a target” is necessary to facilitate the installation of a ferromagnetic target on the turbine, namely its cylindrical section. It also greatly simplifies the placement of a sensitive element at the target - an inductor.

Introduction to the claims of the essential feature: "the target is curved and fixed along the radius of the cylindrical part of the turbine" is necessary to fix the target on the cylindrical surface of the turbine. This allows you to place the sensitive element - the inductor directly in the tube above the cylindrical surface, which requires a minimum of changes in the design of the liquid meter.

The introduction to the claims of an essential feature: “a flat scan of the target (in plan) is made in the form of three identical rectangles connected by two thin jumpers of different lengths” is necessary to create the possibility of determining the speed and direction of rotation of the turbine using one sensing element - an inductor.

On graphic materials are given:

FIG. 1 is a schematic sectional view of an inductive sensor mounted on a tachometric fluid meter.

FIG. 2 is a generalized circuit diagram of an inductive liquid meter sensor.

FIG. 3 - flat scan of the target (in plan).

FIG. 4 - appearance: a) a turbine of a liquid flow meter; b) a curved target of a flat ferromagnetic material.

FIG. 5 is an external view of a liquid meter turbine with a target installed: a) side view; b) front view.

FIG. 6 is a drawing of a flat scan of the target with printed dimensions, where a) is a top view, b) is a side view.

FIG. 7 is an external view of a turbine liquid meter with an inductive sensor (side view).

FIG. 8 is an external view of a turbine fluid meter with an inductive sensor (front view).

FIG. 9 is an enlarged view of a turbine liquid meter (front view of a turbine and a tube with an inductor).

FIG. 10 is a timing diagram of the attenuation at the output of the oscillatory circuit.

FIG. 11 is a diagram for determining the position of a target position on a cylindrical part of a turbine by a microcontroller.

The inductive sensor of the tachometric liquid meter contains a sensing element in the form of an inductor (1) located in the tube (2), which is muffled from one side, at its end. The end of the tube (2) is located near the target (4) fixed on the turbine (3). The inductor (1) is connected by a cable (5) with a capacitor (6), with which it forms an oscillating circuit connected to the microcontroller (7). The turbine (3) is mounted for rotation in the bearing units (8) located in the guides (9) of the housing of the liquid flow meter (10). The capacitor (3) of the oscillatory circuit is connected to a microcontroller (7) located on the electronic circuit board of the inductive sensor device (11), which is hermetically fixed to the housing of the liquid flow meter (10). The turbine (3) consists of two sections: a section with blades (12) and a cylindrical section (13) with a target (4). The target (4) is made of a flat ferromagnetic material, curved and fixed along the radius of the cylindrical part of the turbine (13). The flat scan of the target (in plan) is made in the form of three identical rectangles (14) connected by two thin jumpers of different lengths (15) and (16). The target (4) can be mounted on the cylindrical section (13) of the turbine (3) with glue, and on top of its surface on the entire cylindrical section (13) is additionally fixed with a tape or tube, for example, of heat-shrink material. On the cylindrical part (13) of the turbine (3) during its manufacture, recesses can be made in the shape of the target (4) to be installed. To install the device of the inductive sensor (11) on the body of the liquid flow meter (10), the latter has a hole for installing the tube (2) with an inductor (1), which after installation is located near the target (4) mounted on the cylindrical section (13) of the turbine (3). Between fluid meter body (10) and inductive sensor device

(11) there is a gasket located on the tube (2). The inductive sensor device (11) is attached to the body of the liquid flow meter (10) using threaded connections, for example, screws. This design of mounting the device of the inductive sensor (11) to the body of the liquid flow meter (10) is simple and reliable, and, therefore, low costs for manufacturing, maintenance and replacement if necessary.

The operation of the claimed device is as follows.

The flow of liquid (water) during flow acts on the blades (12) of the turbine (3) installed in the bearing units (8) located in the guides (9) and drives the turbine (3) (together with its cylindrical section (13) with the target ( 4)) in rotation in one direction or another. When rectangles (14) pass through the target (4) connected by two thin jumpers (15) and (16) of different lengths at the inductance coil (1), the latter changes its inductance value. Therefore, in the oscillatory circuit, consisting of a capacitor (6) connected to an inductor (1) using a cable (5), the attenuation parameters of the electrical self-oscillations excited by the microcontroller (7) will change. When thin jumpers (15) and (16) of different lengths pass near the inductor (1), its inductance does not change. Thin jumpers (15) and (16) of different lengths are necessary to simplify the technology of mounting the target (4) on the cylindrical section (13) of the turbine, observing the exact distance between the three identical rectangles (14) of the target (4).

The attenuation rate of the oscillatory circuit formed by the inductor (1) and the capacitor (6) depends on the relative position of the sensing element (inductor (1)) and the portion of the target (4) located in close proximity to it. Due to the digital-to-analog converter (DAC) located on the electronic circuit board of the inductive sensor device (11), the reference voltage necessary to determine the current state of the sensitive element is generated in the microcontroller (7) (see Fig. 1). The signal from the oscillatory circuit after a fixed time after the excitation of the oscillations (hereinafter - ΔT) is fed to the built-in comparator, where it is compared with the level of the DAC. If the amplitude of the oscillations in the circuit through ΔT is less than a predetermined level, then a logical zero appears at the output of the comparator, which corresponds to the state in which the sensing element - inductor (1) is blocked by a rectangle (14) fixed on a cylindrical section (13) from ferromagnetic material target (4) - logical zero (see Fig. 12). On the contrary, if the amplitude of the oscillations in the oscillating circuit through ΔT is greater than a predetermined level, then a logical unit appears at the output of the comparator, which corresponds to a state in which the sensing element - inductor (1) is not blocked by a section with a rectangle fixed to it (14) from ferromagnetic material of the target (4) or blocked by thin jumpers (15) and (16) of different lengths to which the inductor (1) almost does not respond (thin jumpers (15) and (16) of different lengths do not affect the change in the logical unity logic zero). During rotation of the turbine (3), a sequential change in the position of its cylindrical section (13) occurs with rectangles (14) located on it from ferromagnetic material (target (4)).

By analyzing the signal at the output of the comparator, the microcontroller (7) calculates the number of revolutions of the impeller, and also estimates the speed and direction of rotation of the turbine (3). In this case, the microcontroller (7), at each change of the signal at the output of the comparator (six changes of state per revolution), the value corresponding to the volume of water passing over 1/6 of the turbine revolution (3) is added to the current value of water flow. When the microcontroller (7) detects 6 changes in the state of the sensitive element (three sections of successive logical units at the output of the comparator, corresponding to sections a, b, and c (without rectangles (14) from the ferromagnetic material), the rotation direction determination algorithm is started. during which the logical unit was stored at the output of the comparator, the type of sections (a, b or c) and their sequence are determined, so if sections follow in the sequence a-bc (where a <b <c) On the contrary, if the segments follow the sequence cba, the rotation occurs in the counterclockwise direction. When the rotation is fixed in the forward direction, the value corresponding to the volume of liquid passing in one revolution of the turbine is added to the current value of the liquid measured in the forward direction (3).

To achieve energy optimization of the claimed technical solution, an adaptive algorithm is used. The essence of the algorithm is to adapt the number of polls of the sensitive element in accordance with the speed of rotation of the turbine (3). After each full turn, the number of surveys of the sensitive element that was performed during the last turn is checked. If this number becomes less than a certain one (which corresponds to an increase in the speed of rotation of the turbine), then the number of polls of the sensitive element increases. If this number becomes more than a certain value (which corresponds to a decrease in the speed of rotation of the turbine (3)), the number of polls of the sensitive element, the inductor (1), decreases.

The name of the claimed alleged invention "Inductive sensor of a tachometric fluid meter" in relation to analogues and prototype corrected according to GOST 15528-86 "Measuring instruments for flow, volume or mass of flowing liquid and gas" - [4].

We believe that the claimed technical solution "Inductive sensor of a tachometric fluid meter", has all the criteria of the invention, since the totality of the claimed restrictive and distinctive features of the claims were not found when conducting a patent search for such devices and methods of their operation, and therefore meets the criterion " novelty".

The most efficiently proposed device can be used for common house meters of cold and hot water, as well as heating on pipelines with a diameter of more than 40 mm. It has a simplicity of design in comparison with analogues and prototype. Moreover, the device allows you to determine the direction of rotation of the turbine, and, therefore, to determine the volume (flow rate) of fluid flowing through the turbine meter in the forward and reverse directions.

The set of features of the claims of the proposed device is unknown at this level of development of technology, and does not follow from well-known methods (techniques) for creating (constructing) inductive sensors of a tachometric fluid meter, namely:

- to determine the rotation of the tachometer (turbine), only one oscillatory circuit is used, which greatly simplifies the design of both the tachometric (turbine) flow meter and the circuit diagram of the device for measuring fluid flow,

- the target is made of thin ferromagnetic material, and when fixing it on the cylindrical part of the turbine requires a minimum of effort for its installation,

- a relatively light and reliable balancing of the turbine with a fixed (distributed over the surface of the cylindrical part of the turbine) thin target (drilling material of the cylindrical part of the turbine without fixing the weights (weights) can be applied),

proves compliance with the criterion of "inventive step".

The implementation and implementation of the proposed "Inductive sensor tachometric fluid meter" does not present any structural, technical and technological difficulties, which proves compliance with the criterion of "industrial applicability".

Used sources

1. Patent for the invention of the Russian Federation: RU 2238524 C2 dated 10.20.2004, IPC G01F 1/075, G01F 15/075, “Method and device for measuring fluid flow”.

2. Patent of Ukraine: UA 73416 C2 dated 04/15/2005, IPC G01F 1/10, "Liquid meter."

3. Patent for the invention of the Russian Federation: RU 2528614 C2 dated 09/20/2014, IPC G01F 1/10, “Turbine meter for water flow”.

4. Patent for the invention of the Russian Federation: RU 2029915 C1 dated 02.27.1995, IPC G01F 1/10, “Fluid counter”.

5. Patent for the invention of the Russian Federation: RU 2084828 C1 dated 07.20.1997, IPC G01F 1/10, “Turbine flowmeter”.

6. German patent: DE 19725806 (A1) dated 01/28/1999, IPC G01D 5/20, G01F 1/075, G01F 1/115, “Rotation sensor for water meter” - prototype.

7. GOST 15528-86, "Means of measuring the flow, volume or mass of flowing liquid and gas" - Terms and definitions.

Claims (1)

Inductive sensor of a tachometric liquid meter containing a sensing element in the form of an inductor located in a tube plugged at one end of the tube, the end of the tube is located near a target mounted on a turbine made of flat ferromagnetic material, the inductor is connected by a cable to an oscillating circuit capacitor connected to the microcontroller, the impeller is mounted for rotation in the bearing assemblies of the guides of the housing of the liquid flow meter, cond the oscillator circuit sender is connected to a microcontroller located on the electronic circuit board of the inductive sensor device, which is hermetically mounted on the housing of the liquid flow meter, characterized in that the turbine consists of two sections: a section with blades and a cylindrical section with a target, and the target is curved and fixed in radius the cylindrical part of the turbine, and a flat scan of the target is made in the form of three identical rectangles connected by two thin jumpers of different lengths.

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