RU175421U1 - LOCAL SPEED SENSOR - Google Patents

Abstract

The utility model relates to electromagnetic devices for measuring the flow rate of a controlled electrically conductive fluid in large pipelines and can be used in water meters and heat meters. The submersible local speed sensor additionally contains an electromagnet holder and varnish; a fairing and a retaining ring are introduced into the housing unit; two pads for point electrodes, two screen covers were introduced into the electrode assembly; moreover, a varnish cloth electrically insulating the coil from the core is wound on the core, and a coil is wound on the varnish cloth; point electrodes are symmetrically located on the screen from its outer side; wherein the outer diameter of the core sleeve coincides with the outer diameter of the lower end of the sleeve and the diameter of the screen; in addition, a groove is cut out in the holder of the electromagnet and the core is coaxially fixed; in addition, two point electrodes are soldered to the electrode pads, and the screen covers are located coaxially symmetrically with respect to the axis of the submersible local speed sensor; the upper and lower ends of the coil are clamped by a thrust washer and a shield. The technical result is increased reliability and accuracy of measurements of average speed and fluid flow. 1 ill.

Description

The utility model relates to measuring technique, in particular to electromagnetic devices for measuring the flow rate of a controlled electrically conductive fluid in large pipelines.

Known electromagnetic flow meter, which contains a full bore primary converter (sensor) flow, pre-amplifier, current driver, analog-to-digital converter (ADC), a microcontroller, an indicator and a voltage reference source. Electromagnetic flow meters (EMRs) are based on measuring the difference in electrical potentials generated on electrodes in contact with the flow of a controlled moving fluid, perpendicular to both the lines of the magnetic field and the direction of fluid flow. The magnitude of the potentials is determined by the expression E = B⋅D⋅v, where B is the magnetic field induction; D is the distance between the electrodes; v is the local velocity of the controlled fluid. The parameters of the electromagnetic field created by the coils are determined by the current supplied to them from the current driver. The characteristics of this current depend on the signal supplied to the input of the current shaper from the reference voltage source through the reference voltage modulator. The modulation parameters of this signal are determined by the modulator of the modulating signal. The EMF arising on the electrodes goes to the inputs of the pre-amplifier, from the output of which the signal goes to the first input of the ADC. The second input of the ADC receives a signal from the output of the reference voltage modulator, simultaneously with the arrival of this signal at the input of the current driver. The ADC converts the signals into a digital code. The digital signal at the ADC output corresponds to the amplitude of the modulated analog signal at its input. This signal enters the microcontroller, where the interference filtering and filtering of the useful signal, as well as the calculation of the flow rate of the fluid flowing through the pipeline.

Such a technical solution is used in an electromagnetic flowmeter with a full bore primary flow transducer and is used mainly for measuring the flow rate of electrically conductive fluids in pipelines with a diameter of not more than 300-400 mm for measuring the volumetric flow rate of electrically conductive fluids (RF patent 2489684 Electromagnetic flowmeter 2011 ", authors: B .K. Nedzetskiy, VB Rogzin)

The disadvantages of this device are that the magnetic system of the full bore primary flow sensor (PPR) has a design that completely covers the measuring section. With increasing diameter of the flow part of the primary flow transducer (sensor), the mass and consumption of materials, in particular copper for inductors, increase nonlinearly. For example, the mass of PPRR of electromagnetic flowmeters RM-5 (TBN Energoservice, Russia) and AQUAFLUX ("Krohne", Germany) increase from 3-5 kg at DN = 20 mm, up to 95-97 kg at DN = 300 mm and up to 520 kg with DN = 1000 mm. In this regard, the cost of SPPP also increases proportionally with an increase in the diameter of the flow part of SPPP. In addition, in the case of a continuous method for calibrating full bore EMF, it is necessary to set a number of reference flow rates Ge at the inlet to the PPR. The maximum reference flow rate G _max should correspond to the maximum average velocity through the flow part of the SPR u _max = 5-10 m / s. With the growth of the internal diameter D flowing part RPNR desired maximum reference rate G _max increases in proportion to the square of the inner diameter: G _max = u _max πD ^2/4.

A known design PDLS containing a flow sensor in the form of a housing of insulating material, inside of which is placed a coil with a core; on the outer cylindrical surface of the housing are two diametrically located electrodes. The flow transducer is rigidly fixed to the lower end of the hollow rod coaxially with it. The wire harness of the coil and electrodes is passed into the cavity of the hollow rod and enters the electronic unit, rigidly fixed to the upper end of this hollow rod. The electronic unit provides the formation of the supply current of the coil and the processing of the useful signal taken from the electrodes and PDLS. The hollow rod is located inside the lubricator housing, sealed with an oil seal assembly and has the possibility of reciprocating movement by mating in the form of a four-way stop thread on the upper part of the hollow rod and on the nut located in the socket on the upper end of the lubricator housing. The slider has a risk indicator, and a measuring scale is applied on the lubricator case near the groove and in pair they are a measure of the axial displacement of the hollow rod in one direction or another. The lubricator housing is attached to the locking rotary device, which is mounted on the mounting nozzle by means of a quick disconnect.

PDLS with this design is intended for use on pipelines with a diameter of 400 to 1000 mm. The depth of immersion of the PDLS electrodes in the controlled pipeline is set equal to 0.242⋅R, where R is the internal radius of the pipeline according to the scale on the housing-lubricator and at the risk of the index of the slide on the hollow rod. This device allows you to measure the local speed and flow rate of a controlled electrically conductive fluid in large pipelines with a DN of more than 300 mm (certificate for utility model 14783. “Electromagnetic flowmeter” 2000, authors: Abramov GS, Vashurin BC, Zimin M.I. ., Shastunov V.V.).

A disadvantage of the known PDLS is the need to immerse the PDLS electrodes exactly at a depth of 0.242⋅R. Deviation of the immersion depth from this value causes the appearance of an additional systematic error in the flow measurement. The need to ensure accurate adjustment of the depth of immersion determines the complexity and cumbersome design PDLS. In the area of the electrodes, the distribution of the electromagnetic floor is asymmetrical, with an edge effect.

The closest technical solution to the proposed utility model is an electromagnetic local liquid flow meter containing a local speed sensor (primary transducer) and is a sealed cylinder made of non-magnetic material, such as bronze, inside which an electromagnet coil with a magnetic core screwed into the bottom part of the cylinder of the local speed sensor, on the outer end part of which two point electrodes are placed. In this case, the working surface in the area of the electrodes is covered with an insulating washer, which excludes the bypassing of the electric potential generated by the movement of the controlled fluid in the magnetic field of the local speed sensor onto the cylinder body. The insulating washer is usually made of fluoroplastic. If there are suspended abrasive particles in the liquid, the washer is made of wear-resistant polyurethane. The electromagnet is closed by a cover on which two electrical contacts are located, designed to supply voltage to the electromagnet winding. The transmission of voltage pulses from the electrodes to the conversion unit and the electromagnet is powered by a cable, the input of which into the cover is sealed with a rubber plug using a fitting. In this case, the lid is held on the PDLS housing. PDLS is placed in a pipe welded to a controlled pipeline, and is buried in the pipeline by wall thickness, that is, it does not protrude into the pipeline.

Such a PDLS in the composition of electromagnetic local meters allows you to measure the local speed and flow rate of a controlled electrically conductive fluid in pipelines of medium and large diameters from DN 50 mm to DN 500 mm (certificate for utility model 23497 “Electromagnetic local liquid flow meter”, authors: Bobov A. A., Motovilov N.I., Nikiforov M.A. and others).

A disadvantage of the known PDLS for measuring the flow rate of a controlled electrically conductive fluid in large diameter pipelines is: a very narrow range of flow measurement G _min / G _max = _1/25 , where G _max is the maximum measured flow rate corresponding to the average speed of the controlled fluid 10 m / s, G _min - minimum measured flow rate. This is due to the fact that PDLS measures the local velocity in the near-wall region, where the velocity profile changes significantly at flow velocities that do not correspond to the developed turbulent flow regime. This leads to unacceptable values of the relative error (more than 2%) of measuring the average speed and flow rate of the controlled fluid. In the area of the electrodes, the distribution of the electromagnetic floor is asymmetrical, with an edge effect.

The objective of this utility model is to reduce the cost, increase the reliability and accuracy of measuring the average speed and flow rate of PDLS electrically conductive liquid in pipelines with a diameter of ≤300 mm due to the simplification of the PDLS design.

The technical result is achieved by the fact that in a submersible local speed sensor containing a connecting node including a tip and a connector; barbell; wiring harness; a magnetic system including a coil, core, thrust washer; an electrode assembly comprising a shield, two point electrodes and two electrode sealing rings; a housing assembly comprising a sleeve, a fixing screw, a coil screw and two housing sealing rings; in it, in addition to the magnetic system, an electromagnet holder and a varnish cloth are introduced; a fairing and a retaining ring are introduced into the housing unit; two pads for point electrodes, two screen covers were introduced into the electrode assembly; moreover, a varnish cloth electrically insulating the coil from the core is wound on the core, and a coil is wound on the varnish cloth; point electrodes are symmetrically located on the screen from its outer side; wherein the outer diameter of the core sleeve coincides with the outer diameter of the lower end of the sleeve and the diameter of the screen; in addition, a groove is cut out in the holder of the electromagnet and the core is coaxially fixed; in addition, two point electrodes are soldered to the electrode pads, and the screen covers are located coaxially symmetrically with respect to the axis of the submersible local speed sensor; the upper and lower ends of the coil are clamped by a thrust washer and a screen.

In FIG. 1a shows the design of the PDLS assembly.

In FIG. 1b shows the construction of the connecting unit.

In FIG. 1c shows the design of the housing unit.

In FIG. 1g shows the design of the magnetic system.

In FIG. 1d The design of the electrode assembly is shown.

In FIG. 1a shows a pipeline 1 and a PDLS containing a connecting unit 2 (cover (prototype)), a rod 3 (sealed cylinder), a wiring harness 4, a housing unit 5, a magnetic system 6 and an electrode assembly 7.

The figure 16 shows the connecting node 2, containing the tip 8, connector 9, mounting screws 10.

Figure 1c shows a housing assembly 5 comprising a sleeve 11, a fixing screw 12, a screw 13, an unshielded wire 13 ', two housing sealing rings 14, a fairing 15 and a retaining ring 16.

The figure 1 g shows the wires 4 from the coil 18 passing through the groove 17 ', and the magnetic system 6 containing the holder of the electromagnet 17, the coil 18, the core 19 with the hole 19' and the thrust washer 20.

Figure 1e shows a fairing 15 and an electrode assembly 7 containing a screen 21, two shield plates 22, two point electrodes 23 (a sensing element), two o-rings of the electrodes 24, two pads for the electrodes 25. In the design of the PDLS, all of these parts are symmetrically located relative to its axis.

Installation PDLS on the pipeline 1 is shown conditionally (Fig. 1A.). Fastening PDLS to the pipeline is a separate technical solution.

The electrode assembly 7 is hermetically connected to the fluoroplastic fairing 15 using two sealing rings of the electrodes 24, and the outer surface of the electrodes 23 is flush with the bottom surface of the fairing 15. The tightness between the fairing 15 and the sleeve 11 is ensured by two sealing housing rings 14. The fairing 15, which fixes the ring 16, the sleeve 11 are interconnected by a screw 12. The outer surface of the retaining ring 16 is flush with the surface of the fairing. The end of the sleeve 11 is welded to the lower end of the rod 3, the upper end of the rod 3 is welded to the tip 8 (Fig. 1A).

The screw 13 is screwed into the sleeve 11. An unshielded wire 13 'is attached to the screw 13, passing inside the rod 3 and connected to one of the contacts of the connector 9.

The wires of the bundle 4 from two point electrodes 23 pass through the hole 19 'in the core of the electromagnet 19, then through the central hole of the sleeve 11, then inside the rod 3 and are connected to the contacts of the connector 9. The wires of the coil 18 pass through the groove 17' in the holder of the electromagnet 17, then through the Central hole of the sleeve 11 are combined inside the rod 3 into a wiring harness 4 and attached to the contacts of the connector 9.

Two point electrodes 23 are located and soldered on the contact pads of the electrodes 25. Two shield plates 22 are aligned and symmetrical with respect to the coil 18 opposite the lower end of the magnet sleeve 17 and the lower end of the core 19. The widths of the core of the magnet 19 and the holder of the magnet 17 coincide with the width of the two shield plates 22 (Fig. 1a, d, sec. A-A, view B). This provides good electrical contact between the holder of the electromagnet 17, the core 19, the contacting sleeve 11, the screw 13 and the unshielded wire 13 '. The upper and lower ends of the coil 18 are clamped by a thrust washer 20 and a shield 21. The holder of the electromagnet 17 together with the core 19 form a magnetic circuit that forms the necessary configuration of the magnetic field with minimal scattering. The point electrodes 23 are as close as possible to the magnetic field with maximum induction. This result was obtained by introducing an electromagnet cage 17, two plates 22, two pads for electrodes 25 on the screen 21. Protection of the point electrodes and unshielded wires of the coil from the penetration of external electromagnetic interference is provided by the connection of the screen lining, magnetic and case systems. In this case, the screen of wires 4 'from the point electrodes 23 is connected to one of the contacts of the connector 9 (Fig. 1a). The locking ring 16 provides a reliable mechanical connection between the fairing 15 and the sleeve 11. The tight connection of the cage 17 with the fairing 15 protects the magnetic system 6 and the electrode assembly 7 from moisture. The positioning of the point electrodes 23 flush with the bottom of the fairing 15 increases the sensitivity of the PDLS.

Thus, the design of the inventive PDLS consists of a connecting node 2, which contains a tip 8, connector 9 and the fixing screws of the electrical connector 10; rods 3, wiring harness 4; a magnetic system 6, including a coil 18, a core 19, a thrust washer 20; an electrode assembly 7 including a screen 21 comprising two point electrodes 23, two o-rings of electrodes 24; housing unit 5, which includes a sleeve 11, a fixing screw 12, a screw 13, two housing sealing rings 14, the following are additionally introduced in the design of PDLS:

- the composition of the magnetic system - the holder of the electromagnet 17 and varnish, which is wound on the core and isolates the core from the coil wound on top of the varnish;

- the structure of the housing unit - a cowl 15 of insulating non-magnetic material and a retaining ring 16;

- the electrode assembly consists of two shields 22 and two pads for point electrodes 25;

moreover, the outer diameter of the holder of the electromagnet 17 coincides with the outer diameter of the sleeve 11 and the diameters of the shields 22; in addition, in the holder of the electromagnet 17, the core 19 is coaxially fixed. Two plates of the screen 22 are fixed on one surface of the screen 21 (Fig. 1e, section AA), and on the other surface are fixed two pads 25 for the point electrodes (Fig. 1e, view B). The upper and lower ends of the coil 18 are sandwiched between the thrust washer 20 and the screen 21, which forms a frame for protecting the coil.

PDLS is the primary converter for operation in electrically conductive and even aggressive environments at temperatures up to 150 ° C with overpressure up to 16 kgf / cm. Therefore, the electrodes 23, the sleeve 11, the rod 3, the locking ring 16, the tip 11 are made of stainless steel (Fig. 1A). The holder of the electromagnet 17 and the core 19 are made of electrical steel (Fig. 1d). Screen 21 (Fig. 1e) is made of double-sided foil fiberglass with a thickness of 0.5 mm, grade STK. The plates of the screen 22, the pads for the electrodes 25 for mounting two electrodes are formed of a conductive layer of fiberglass according to the technology of manufacturing printed circuit boards. The coaxially-symmetric arrangement of the screen plates relative to the coil provides good electrical contact between the ferrule of the electromagnet in contact with the sleeve, all of which are connected to the screw 13 and the wire 13 '. This protects the electrodes 23 and coil 18 from penetration of external electromagnetic interference (Fig. 1a). Unshielded wires from the coil, from the screw of the coil and shielded wires from the electrodes are protected from penetration of external electromagnetic interference by the monolithic design of PDLS. The monolithic design of PDLS is an electromagnet ferrule 17 structurally interconnected, a sleeve 11, a retaining ring 16, a rod 3 and a tip 8. An electromagnet ferrule and a rod are connected to each other by welding.

The sleeve 11 is connected to the holder of the electromagnet 17 by a threaded connection (Fig. 1a, c, d).

The core 19 with varnish wound on it and a coil 18 (a cylindrical coil) are connected to the ferrule of the electromagnet 17 by pressing (Fig. 1d).

The point electrodes 23 are connected by soldering to the pads 25 under the point electrodes, the screen 21 is connected to the holder of the electromagnet 17 by the method of soldering.

The fairing 15 is worn on the electrode assembly 7, the holder of the electromagnet 17 and is attached to the sleeve 11 by a locking ring 16 and a fixing screw 12.

The sleeve 11 and the rod 3 are interconnected by welding.

All the above details in the design of the PDLS, including the fixing screw 12, are made by the applicant, i.e. LLC TBN Energoservice. Standard purchased items include: screw 13; O-rings 14 and O-rings of electrodes 24. Wiring harness 4, winding wire for coil 18, varnished fabric, connector. The materials from which the sealing rings are made, the coatings of the wire harness and the wires of the winding, the varnish brand is selected in accordance with the operating conditions.

After the manufacture of PDLS, it is calibrated at a specialized stand, the basic metrological characteristics are determined, a passport for each sample of PDLS is compiled.

Main characteristics of the submersible local speed sensor.

Length L, mm - 283.4; 333.4; 383.4.

Diameter D, mm - 37.

The speed of the controlled fluid, m / s - 0.2 .... 10.

Supply voltage U, V - 12.

Coil current I, A - 0.3.

The operating temperature range of the controlled fluid is Θ, ° С - 0 ... 150.

Service life hours, 12 years.

The functioning of the PDLS (Fig. 1a) in the process of determining the flow rate of an electrically conductive liquid in large diameter pipelines occurs when the pipeline 1 is completely filled with controlled liquid, the coil 18 from the magnetic system 6 is fed with an alternating pulse voltage U = 12B. External voltage to the coil comes from connector 2 through connector 9 and cable harness 4 (Fig. 1a, b). The supply voltage in the coil circuit creates an alternating magnetization current I, inducing an alternating magnetic field B, which induces an alternating signal (voltage) U _{± v} proportional to the local velocity v of the controlled fluid in the pipeline under the influence of a moving conductive fluid in the electrode assembly 7 on the point electrodes 23. The power of the coil 18 over time can vary over a wide range of parameter values. For example, the parameters can be as follows: the pulse repetition period is T = 2 s, the duration of each pulse is T ₁ = 360 ms, the leading edge of the pulse is shifted relative to the trailing edge by a pause time of T ₀ = 640 ms, during this time interval the current does not flow through the coil, that is, from an industrial network, the device does not consume electricity. Such a pulsed power supply of the coil allows to save 64% of the consumed electric power in comparison with continuous power supply. Then, using the values of analog or digital signals proportional to the local flow velocity v, the average cross section velocity u and the volume flow rate G of the controlled fluid are calculated.

The principle of operation of the PDLS is based on the interaction of a moving controlled electrically conductive fluid with the magnetic field of the magnetic system 6 of coil 18 (figa, d) when the pipeline 1 is filled with a moving electrically conductive fluid. The magnetic system 6 creates a magnetic field in the local region near the point electrodes 23. When the controlled fluid moves in a magnetic field, an EMF is induced, inducing a signal U _{± v} on the electrodes 23 proportional to the local velocity v at the measuring points and the volumetric flow rate G.

Thus, the combined actions of known and unknown distinguishing features in the utility model formula give new technical solutions, which favorably reduces the error in measuring fluid flow, significantly reduces the energy consumption from the industrial network (by 64%), and thanks to these useful properties, the scope of the proposed useful models. The cost of PDLS is reduced by winding a coil without a frame on the core. Reliability is increased due to the use of stainless steel in the design of PDLS, the introduction of plates, pads for point electrodes on the screen. The measurement accuracy is improved by reducing the scattering of the magnetic field, increasing the sensitivity of PDLS, protecting the SE from the effects of external industrial electromagnetic interference, which increases the signal-to-noise ratio. These new properties of the utility model favorably differ from the selected analogue and prototype, determines, according to the applicant, the utility model meets the criterion of "inventive step". To implement the utility model, well-known domestic materials were used in the field of the electrical industry and using algorithms and software developed by TBN Energoservice LLC to determine the flow rate in a conductive fluid with high accuracy (relative error of not more than 1-2% depending on the range flow measurements) in pipelines of large diameters. This circumstance, according to the applicant, allows us to conclude that the utility model meets the criterion of "industrial applicability".

To improve the accuracy of measuring submersible sensors of local speed and flow rate of electrically conductive fluid, OOO TBN Energoservice conducted an experimental study on the UROKS-400 torrential installation.

The experiment was conducted on prototypes of a modernized flowmeter RM-5-B3, designed to measure and commercialize the volumetric and mass flow rate, volume and mass of the electrically conductive liquid in large pipelines, as well as for use in automated systems for metering, control and regulation of the amount of heat. In the course of the experiments, the following result was obtained: the relative error in the flow measurement does not exceed 2% when the average flow velocity of the measured liquid changes in the range 0.4 - 3..5 m / s, which corresponds to the requirements of the Methodology for the commercial accounting of thermal energy, coolant, approved by order of the Ministry of Construction and Housing and Communal Services of the Russian Federation dated March 17, 2014 No. 99 / PR, according to which flowmeters, including flowmeters with electromagnetic immersion sensors of local speed, up to It is false to provide a measurement of mass (volume) with a relative error (E _ƒ ):

class 2: E _ƒ = ± (2 + 0.02G _max / G), but not more than ± 5%; (12.7),

class 1: E _ƒ = ± (1 + 0,0lG _max / G), but not more than ± 3,5%, (12.8),

where E _ƒ is the relative error of the flow meters, G _max is the maximum measured flow rate, G is the current value of the measured flow rate.

PDLS allows you to display on an alphanumeric indicator:

- the current value of the volumetric flow rate for each pipeline where the local speed sensors are installed, m ³ / h;

- the current value of the mass flow rate for each pipeline where local speed and temperature sensors are installed, t / h;

- volume cumulatively for each pipeline where local speed sensors are installed, m ³ ;

- mass on an accrual basis, for each pipeline where local speed and temperature sensors are installed, t;

- the current value of the temperature of the medium for each pipeline where temperature sensors are installed, ° C;

- the current value of the pressure of the medium in the pipelines for each pipeline where pressure sensors are installed, kgf / cm ² and MPa;

- current values of ambient temperature (when completing the device with appropriate sensors), ° С;

- operating time, h;

- current date and time values;

- information about the modification of the device, its settings and status. The information indicated above can be transmitted digitally via the RS-485 interface (and, together with peripheral devices, and through the RS-232 interface) to a personal computer and / or to automated heat metering, control and regulation systems.

The RM-5-B3 flowmeter provides archiving in non-volatile memory of the hourly, daily, monthly, weather values of the mass and volume of the monitored liquid, the values of the measured parameters of the liquid (flow, temperature), operating time, etc.

The archive depth is at least:

- hourly - 45 days;

- daily - 12 months;

- monthly - 5 years;

- weather - 32 years;

- events - 16 thousand records.

Power supply RM-5-B3 is carried out from an alternating current network with voltage from 187 to 242 V, frequency from 49 to 51 Hz.

Claims (1)

Submersible local speed sensor containing a connecting node that includes a tip and a connector; barbell; wiring harness; a magnetic system including a coil, core, thrust washer; an electrode assembly comprising a shield, two point electrodes and two electrode sealing rings; a housing assembly comprising a sleeve, a fixing screw, a coil screw and two housing sealing rings, characterized in that it additionally includes an electromagnet holder and varnish; a fairing and a retaining ring are introduced into the housing unit; two pads for point electrodes, two screen covers were introduced into the electrode assembly; moreover, a varnish cloth electrically insulating the coil from the core is wound on the core, and a coil is wound on the varnish cloth; point electrodes are symmetrically located on the screen from its outer side; wherein the outer diameter of the core sleeve coincides with the outer diameter of the lower end of the sleeve and the diameter of the screen; in addition, a groove is cut out in the holder of the electromagnet and the core is coaxially fixed; in addition, two point electrodes are soldered to the electrode pads, and the screen covers are located coaxially symmetrically with respect to the axis of the submersible local speed sensor; the upper and lower ends of the coil are clamped by a thrust washer and a screen.

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