WO2008037897A1

WO2008037897A1 - Device for measuring the flow rate of one of the constituents of a multiphase fluid flowing in a conduit

Info

Publication number: WO2008037897A1
Application number: PCT/FR2007/001587
Authority: WO
Inventors: Pascal Stabat; Bruno Pilliot; Jérôme Roussel
Original assignee: Veolia Proprete
Priority date: 2006-09-28
Filing date: 2007-09-27
Publication date: 2008-04-03
Also published as: FR2906609B1; FR2906609A1

Abstract

The invention relates to a device for measuring the flow rate of at least a first constituent of a multiphase fluid flowing axially in a conduit having a favoured axis by measurement of friction noise generated by the first constituent of the multiphase fluid, the measurement device comprising a non-intrusive noise detector linked to an outer face of the conduit, at least one obstacle added to the inside of the conduit and formed by at least one metal lamella comprising at least one portion that extends axially in the conduit and at least one segment connecting the portion with the conduit. According to the invention, the portion forms, with the segment, in a plane comprising the axis, a predetermined non-zero angle.

Description

Device for measuring the flow rate of one of the constituents of a multiphasic fluid flowing in a conduit

The present invention relates generally to the field of sensors for measuring the flow rate of one of the constituents of a fluid or a multiphase flow flowing in a conduit.

More specifically, the invention relates to a device for measuring the flow rate of at least a first component of a multiphase fluid flowing in a conduit by measuring a friction noise generated by the first component of the multiphase fluid, the device measuring device comprising a non-intrusive noise detector connected to an outer face of the duct.

As a preliminary, note that the flow control, for example, of a solid phase in the multiphasic fluid, for example, of the "gas / powder" type, is of great importance for various industrial processes involving pneumatic transport of particles, for example, to regulate a good operation of a combustion furnace, particularly in the combustion of waste for which the treatment of fumes requires precise control of the reagents used.

A first approach is to control the solid phase (powder) before mixing with a gas phase (air), that is to say, to evaluate a quantity of particles entering the pneumatic conduit. In known manner, machines with worms are used to feed the pneumatic conduits. A simplistic solution consisting of measuring, for example, a speed of rotation of the worm to control the quantity of the powder conveyed to the conduit, is not satisfactory. Indeed, the rotation of the worm in no way guarantees the actual supply of the material in the pneumatic conduit.

Another approach is to measure the flow rate of the solid phase in the multiphase fluid already formed in the pneumatic conduit. It should be noted that these measurements are particularly delicate for powders. Indeed, the latter tend to charge static electricity which disrupts most existing sensors, for example, ultrasonic sensors or microwaves. To circumvent this difficulty, devices are used in a known manner measuring the friction noise produced during the passage of the multiphase flow in the pneumatic conduit.

As illustrated in Figures 1 and 2 of the state of the art, such a device is well known to those skilled in the art, specialist pneumatic conveying granular materials or powders S in a conduit 1, including for example as the describes an instruction manual published by the company SIEMENS ^® in August 2005 (referenced 7ML19985DM02) and relating to a sensor SITRANS ^® AS 100. This is a non-intrusive probe 2a, 2b called stable acoustic high frequency (from 75 kHz to 175 kHz). The probe is installed, for example, directly on an outer face 12 of the duct 1 (FIG. 1, probe 2a) or on a rigid support 7 integral with a flange 10 connecting two parts of the duct 1 (FIG. 1, probe 2b) and of preferably on the concave part of an elbow (Figure 1). It should be noted that an installation of a solid particle sensor on the convex portion of the elbow of the pneumatic conduit is described in Japanese Patent JP 59163521. As shown schematically in FIG. 1, the solid particles S constituting the granulated material, in suspension in the flow of compressed air GS, rub, during their displacement along the preferred axis AB of the duct 1, against the face internal duct 1. The resulting acoustic emissions propagate through the wall 11 of the duct 1. The probe picks up the friction noise by delivering at its output a signal, for example, an analog voltage signal in Volt or electric current in mA, proportional to the friction noise and therefore to the flow rate of the solid particles in the duct 1.

Typically the SITRANS ^® AS 100 sensor is used in the field of industrial process protection for monitoring and early warning purposes. An alert is emitted by the interface of the sensor 2a, 2b to an operator as soon as the flow rate of the solid phase S exceeds a predetermined threshold value. Thus, expensive process interruptions and / or mechanical failures due to an unexpected drop and / or failure of the solid phase (particles) S in the multiphase GS flow of the "air / powder" type can be avoided. A note referenced 7ML1996-5AN13 and published by the company SIEMENS ^® in the first half of 2006 on www. siemens. com / processprotection describes an example of using the sensor to monitor the very high rate of pulverized coal fed to a furnace operating at 1200 ° C in a steel plant.

However, the measuring range of the SITRANS ^® AS 100 sensor and / or its resolution are not always satisfactory. For example, despite its two sensitivity ranges (high and low) to friction noise corresponding to its two operating ranges, the resolution of the sensor SITRANS ^® AS 100 may be insufficient to the extent that its installation on straight portions of the duct 1 as that illustrated in Figure 2, is formally discouraged by SIEMENS ^® because of the weak acoustic emissions resulting in this case from a limited friction between the particles S and the inner face 13 of the duct 1. The presence in the duct 1 of at least one bent portion 101 whose preferred axis AOB forms an angle α such that α <180 ° (Figure 1), is strongly recommended to obtain a good measure. Otherwise, installed on the straight portion of the duct 1 (Figure 2), the SITRANS ^® AS 100 sensor can be inoperative even for multiphase flows "air / powder":

With high concentrations of the solid phase, for example, several kilograms of powder per m ³ of air; and or

With large S-particles, for example, greater than 1 mm in diameter, that is to say, even for cases where a strong friction between on the other hand, the large particles S with a lot of inertia tilting each other, including in the straight portions because of the turbulence present in the duct 1, and, on the other hand, the internal face 13 of the duct 1 (FIG. 2).

As for the multiphase flows "air / powder" very poor in particles for which one can expect a priori a very low friction between the small particles having little inertia and the inner face 13 of the duct 1, the signal is too weak to be exploited even by a sensor of the SITRANS ^® AS 100 type not only when it is installed on the straight portions of the duct 1 (FIG. 2), but also when it is installed on the bent portions 101 of the duct 1 (FIG. perfect compliance with the manufacturer's recommendations described in the manual 7ML19985DM02. However, the monitoring of a low flow rate of the solid material in a multiphase flow, for example, flow rates of less than 5 kg / hour, is important in particular for powdery reagents conveyed by pneumatic transport and intended for continuous treatment of fumes. for example, fumes from combustion furnaces in incineration plants.

In addition, as described in the manual 7ML19985DM02, page 6, the installation of the sensor on non-metallic surfaces that attenuate acoustic emissions should be avoided. In other words, the sensor according to the state of the art is unsuitable for measuring the flow rate of a solid phase in a multiphase flow in flow, for example, in plastic conduits which are nevertheless widely used in the field of pneumatic transport.

Various solutions which have been the subject of patent applications, have been developed to increase the friction noise of the solid phase flowing in the ducts, without achieving conclusive results in the tests with the powdery reagents present in small quantities in multiphase flows and used to treat fumes from combustion furnaces in incineration plants.

In this context, the purpose of the present invention is to propose a measuring device free of any least of the limitations mentioned above, and in particular adapted to measure a low flow rate of the solid phase of the multiphase flow, including in straight portions of the conduits and / or in non-metallic conduits.

For this purpose, the measuring device according to the invention comprises:

On the one hand, a non-intrusive friction noise detector connected to an outer face of the duct in which a multiphase fluid flows in accordance with the generic definition given in the preamble above; and,

• on the other hand, at least one obstacle reported inside the conduit.

The presence of the reported obstacle inside the duct amplifies the acoustic emissions and, therefore, the friction noise produced by the particles, because to the impacts of the particles against the internal face of the duct are added the impacts of the particles against the 'obstacle. The latter can then play the role of a "sound box". With this arrangement, the friction noise is amplified so as to make discriminant by a non-intrusive high-frequency steady acoustic sensor, for example, by the sensor SITRANS ^® AS 100, even for multiphase flow "air / powder" with low concentrations of the solid phase and / or with small solid particles, and even in the absence of a bend in the conduit.

It should also be noted that the measuring device according to the invention is insensitive to changes in the electrostatic charge of the powder.

In the preferred embodiment of the invention, the measuring device according to the invention is characterized in that the obstacle comprises at least a portion extending along a preferred direction of flow over a predetermined length.

This structure makes it possible to further amplify the acoustic emissions and, therefore, the friction noise produced by the particles. Indeed, the pneumatic transport of the powder in the duct is generally performed at high air speeds which correspond to Reynolds number values well above 2000, and in particular to Reynolds number values of about 40,000. Recall that these values of the Reynolds number correspond to a flow regime with a developed turbulence, characterized by a presence in the multiphase flow vortices and / or vortex lines of different sizes that stir the solid particles. Thus, in addition to the global displacement of the particles taken together with the multiphase flow along the preferred axis of the conduit in the direction of flow, each of the particles moves individually to the local scale according to a random direction, for example, in an inclined direction, or even opposite direction of flow, determined by the local vortex. In the absence of the portion of the object extending along the preferred direction of flow over a predetermined length, the probability that a particle that has struck the obstacle a first time at the first impact will return to produce a second impact remains weak. In other words, the contribution in the friction noise of the global displacement of the particles as a whole outweighs that of the local displacement of each of the particles. In a very schematic way, this means that a particle only produces an impact against the obstacle. On the contrary, in the presence of the portion of the object extending along the preferred direction of flow over a predetermined length, the probability that the particle that hit the obstacle the first time during the first impact, return to produce the second, third or even fourth impact remains high. In other words, the more the object is extended along the preferred direction of the flow, the greater the probability of the same particle impacting it several times, following the swirling lines enveloping the obstacle. Thus, the extended portion of the object plays a role in amplifying the number and / or the intensity of the acoustic emissions and, in fine, the measured friction noise.

It is possible to provide that the obstacle is formed by at least one metal strip. Thanks to the slat-shaped obstacle it is possible to predictably disturb the multiphase flow in the duct in order to regulate the formation, the number and the intensity of the swirling lines enveloping the obstacle and consequently , the number and intensity of the impacts of particles tapping into the coverslip. In addition, the metal having a range of elastic deformation, the metal strip transmits acoustic waves without almost attenuate them. In addition, it can advantageously vibrate because of the agitation produced by swirling lines enveloping the obstacle. It should be noted that these vibrations are of aerodynamic nature independent of the flaps of the lamella induced by the impacts mentioned above. solid particles brewed by the vortices. Thus, the obstacle in the form of the metal strip can emit acoustic emissions with, for example, two distinct carrier frequencies, a first frequency being, for example, representative of the impacts of particles and a second frequency representative of the aerodynamic vibrations. The second carrier frequency offers the possibility of verifying the correct operation of the sensor independently of the presence of the solid phase in the flow by increasing the reliability of the measuring device according to the invention.

It is also possible to provide that the obstacle cooperating with the flow of the multiphase fluid in the duct generates the friction noise at least in a high frequency range, such as between preferably about 75 kHz and about 175 kHz. Note that the high frequency acoustic emissions make the measuring device less sensitive to surrounding noise and / or other parasitic industrial vibrations that may exist in the pneumatic conveying circuit, for example, the vibrations induced by the fan supplying the circuit with air.

According to a particular embodiment, the measuring device according to the invention can comprise:

At least one means for regulating a gas phase of the multiphase fluid flowing in the conduit,

At least one means for regulating a solid phase of the multiphasic fluid flowing in the conduit,

At least one management equipment linked by at least one electrical and / or fluid link with the noise detector and with at least one of the means for regulating the multiphasic fluid flowing in the conduit. Thus, the pneumatic conveying circuit provided with the measuring device according to the invention can be regulated autonomously, without any intervention by the operator.

It is also possible to provide a means selectively absorbing the friction noise is arranged between the friction sensor and the conduit. This makes it possible to adjust the friction noise to the sensitivity of the sensor, thus avoiding its saturation.

According to another embodiment, the measuring device according to the invention comprises at least two noise detectors installed respectively at two predetermined predetermined distances from the obstacle. This makes it possible to produce at least two measurements at the same time by increasing, for example,

The reliability of the measuring device according to the invention, and / or

The extent of measurements and / or the resolution of the device according to the invention.

The process safety that results is particularly important in an industrial setting, for example, to avoid a priori any accidental release of dioxins following a rupture of supply of granular reagent by pneumatic transport of a reactor in a treatment plant. waste.

In a preferred embodiment, the obstacle according to the invention extended through a wall of the duct, solidly with it, forming a lug on the outer face of the duct. This extension of the obstacle towards the outside of the duct makes it possible to facilitate its installation and / or its selective fixing on the duct, for example, by means of a weld or a clamping (including so adjustable compared, for example, to the preferred axis of the conduit), whatever the form (and / or location) of the conduit. Similarly, the lug transmits to the outside of the duct acoustic emissions produced inside the duct by the impacts of the particles against the obstacle and aerodynamic vibrations induced by the vortex lines.

It is then possible to provide that the noise detector is arranged on the pin, the detector with the pin forming a measurement unit. This structure makes it possible to measure the acoustic emissions produced inside the duct even when the duct is formed by an acoustic emission-absorbing material, for example when the duct is made of plastic. Thanks to the lug, it is possible to install the detector selectively in any place of the duct, including in an adjustable manner with respect, for example, to the privileged axis of the duct.

It is also possible to provide that the measuring device according to the invention comprises at least two measurement units installed according to one of the configurations chosen from the following configurations with respect to the preferred direction of flow: (a) in parallel ; (b) in series. This structure makes it possible to adjust the intensity of the friction noise regardless of the concentration of the solid phase in the "air / powder" flow and / or the size of the solid particles displaced by the pneumatic transport and, in particular for noise measurements. friction in multiphase flows very poor in particles, such as:

• with low concentrations of the solid phase, for example, less than about 0.1 kg of the phase solid per m ³ of air and in particular with concentrations of between about 0.02 kg of the solid phase per m ³ of air and about 0.1 kg of the solid phase per m ³ of air; and or

• with small S particles, for example, less than 1 mm in diameter and, in particular, with sizes smaller than 0.1 mm in diameter.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

FIG. 1 represents a view of the measuring device according to the state of the art with two friction noise sensors installed near a bent portion of the duct (assembly recommended by the supplier of the sensor),

FIG. 2 represents a view of the measuring device according to the state of the art with two friction noise sensors installed on a straight portion of the duct (assembly not recommended by the supplier of the sensor),

FIG. 3 represents a schematic view of the pneumatic conveying installation using the device according to the invention for measuring the flow rate of the powder transported by the flow of pressurized air flowing in a conduit,

FIG. 4 shows a portion of the duct in partial section along the preferred axis of the duct, the portion of the duct being equipped with the measuring device according to various embodiments of the invention as follows 4a) with the sensor of the invention. friction noise disposed on the outer face of the duct and the reported obstacle formed by a rectangular metal strip rounded with the pin; 4b) with two friction noise sensors arranged on two pins in series and the two reported obstacles each formed by a rectangular metal strip with the lug; 4c) with two friction noise sensors arranged in series on the outer face of the duct and the obstacle formed by a metal strip obtuse with the lug; 4d) with the reported obstacle formed by the rounded rectangular metal strip with the lug and the friction noise sensor, installed on a bent portion of the duct; 4e) with the friction noise sensor disposed on the outer face of the duct and the reported obstacle formed by a resonant chamber filled with a predetermined load,

FIG. 5 represents a portion of the duct in partial section perpendicular to the preferred axis of the duct, the portion of the duct being equipped with the measuring device according to various embodiments of the invention as follows: 5a) with the reported obstacle without ergot; 5b) with the obstacle reported with the pin; 5c) with two obstacles arranged in parallel in the conduit,

FIG. 6 represents an operating diagram of one of the embodiments of the measuring device according to the invention installed in a portion of the duct in partial section along the preferred axis of the duct.

Figures 1 and 2 representing the state of the art have already been described above and will not be detailed below. FIG. 3 schematically represents an example of a pneumatic conveying installation G of pulverulent reactants S for a treatment of flue gases leaving a combustion furnace (not shown in FIG. 3). This case concerns the treatment of gaseous effluents before their release into the atmosphere by an incineration plant. The powdery reactants S comprise small particles, for example less than 1 mm in diameter and, in particular, with sizes smaller than 0.1 mm in diameter.

Existing technologies allow continuous measurement of gas contents such as CO, HCL, SO ₂ , NO _x etc. present in the smoke from incineration plants before being released into the atmosphere. Therefore, it is possible to treat these gases continuously to minimize these contents by selectively injecting, for example, into a reactor R downstream of the combustion furnace, corresponding reagents such as lime for HCl and SO ₂ , or good urea for NO _x . Similarly, there can be permanent control over CO releases while adapting the combustion in the furnaces to reduce these releases.

However, no technology to date can continuously measure dioxins discharged into chimneys and validate the proper functioning of their treatment. However, the impact of dioxins on the environment and their harmfulness in terms of public health are such that it is essential to ensure their effective and continuous treatment downstream of the combustion furnace before the discharge of fumes into the atmosphere. . To do this, the powdery reactants S are permanently brought in a predetermined amount up to, for example, R reactor. downstream of the combustion furnace using the duct 1, for example, in the form of a ventilated duct. The pneumatic transport of the powdery reactants S is ensured, in a known manner, by a flow of air G initiated in the duct 1, for example by a fan 5.

The reactants S are conveyed in the duct 1, for example by means of a worm machine 4 via a pipe 46. The worm 45 rotates thanks, for example, to a geared motor comprising a motor 43 and a gearbox 44. Thus, the rotational speed of the worm 45 can vary, for example, from 2 to 10 revolutions per minute depending on the setting of the geared motor.

In one embodiment of the invention, the powdery reactants S are injected into the pipe 1 by means of a rotary lock (not shown in FIG. 3) installed in the pipe 46 downstream of the pipe. worm 45 and upstream of the ventilated duct 1.

The worm 45 is fed, for example, under the effect of the gravity P (FIG. 3), from a bag 41 containing the pulverulent reactants S, via a funnel 42 arranged laterally and radially with respect to an axis. privileged of the worm 45.

In another embodiment of the invention, the worm 45 is driven using a frequency converter (not shown in Figure 3). Thus, the rotational speed of the worm 45 can advantageously vary according to, for example, the level of the reagents in the bag 41. Similarly, the frequency converter can program an increase or a reduction of the rotational speed of the worm 45 according to the evolving needs of the reactor R, for example, during a stopping and starting phase of the furnace of combustion. It should be noted, however, that the rotation as such of the worm 45 does not in any way guarantee the actual supply of the solid material, that is to say the reagents S, precisely requiring it to be measured in the pneumatic conveying circuits, as mentioned above.

In the present nonlimiting example, the amount of powder S injected into line 1 per hour remains less than 5 kg / h and, in particular, equal to or less than 4.5 kg / h. As for the Reynolds number representative of the flow in the duct 1, it is equal to, for example, approximately 40,000.

As can be seen in FIG. 3, the mixture of the air G pushed by the fan 5 with the reagent S conveyed by the worm 45 takes place in the duct 1, forming the multiphase flow GS of the "air" type. with low concentrations of the powder S, for example, less than about 0.1 kg of the powder S per m ³ of air and, in particular with concentrations of about 0.02 kg of the powder S per m ³ of air and about 0.1 kg of powder S per m ³ of air. The latter flows in the duct 1 in the direction of the reactor R along the arrow AB (from left to right in Figure 3) which coincides with the preferred axis of the duct 1, for example its axis of symmetry AB.

In another embodiment, the pneumatic conveying installation can comprise several worms 45 arranged, for example in series along the preferred axis AB of the conduit 1. Each of these screws 45 can supply the conduit 1 with reagents specific, for example in powders of different diameters. Similarly, Other than the carrier air can be brought into the conduit 1. Thus, the multiphasic fluid GS may comprise not only several phases but also different constituents of the same phase. Similarly, reactions, for example, of a chemical nature, can take place during the flow of the multiphase fluid GS upstream of the reactor R in the duct 1.

A detector 2 non-intrusive high-frequency steady acoustic from 75 kHz to 175 kHz of standard type with power supply 20 to 30 volts DC and an analog output of 0.08 to 10 volt DC, for example, SITRANS ^® sensor SIEMENS ^® , can be installed on a portion referenced UU of the duct 1. The detector 2 can be installed directly on the duct 1, as shown in Figure 3. In another variant of the invention, the detector 2 can be installed on an integral part of the conduit 1, for example, on a bracket 20 (Figures 4a, 4c, 4 e). In the case of the metallic conduit 1, for example made of steel, the bracket 20 can be welded or fixed by mechanical clamping on the outer face 12 of the conduit 1.

The portion UU carrying all the elements of the measuring device according to the invention may be a sleeve 15 that can be inserted at any point of the duct 1 as shown in FIG. 3. It can be arranged at the entrance of the R reactor to detect the amount of powder S injected closer to the fumes. The sensor 2 measures the friction noise generated by at least one of the components of the solid phase S of the multiphase fluid GS, for example, by the powder S.

As shown in the example in FIG. 3, the installation of the pneumatic transport can comprise at least one management equipment 6 linked by at least one electrical link (for example, by a wireless communication means) and / or fluidic means (for example, by pneumatic means) with the noise detector 2 and with at least one One of the means for regulating the multiphasic fluid GS flowing in the duct 1. As mentioned above, the means for regulating the multiphase fluid GS may comprise at least one means for regulating a gas phase G such as the fan 5. and / or at least one means for regulating a solid phase S such as the worm machine 4 45.

At least one obstacle 3 is attached inside the duct 1 and disposed, for example, upstream of the sensor 2 with respect to the preferred direction AB of the flow of the multiphase fluid GS. It is preferably made of non-absorbing acoustic wave material, in particular the waves in the high frequency range which starts at the audible frequency limit, for example, from about 15 kHz, and preferably between about 75 kHz and about 175 kHz. For example, the obstacle 3 is made of metal such as stainless steel. Thus, the obstacle 3 cooperating with the flow of the multiphase fluid GS in the duct 1 generates the friction noise at least in a high frequency range which begins at the limit of the audible frequencies, for example, from about 15 kHz, and in particular preferably between about 75 kHz and about 175 kHz.

As shown in Figures 3, 4 and 6, the obstacle 3 comprises at least a portion 31 extending along the preferred direction AB of the flow over a predetermined length LO. The obstacle 3 can be installed on a straight part of the duct 1 (FIGS. 2, 4a-c, 4e, 6) or on a curved part of the duct 1 (FIG. 4d). It should be noted that the right part or the curved part of the duct 1 can be formed by the sleeve 15 respectively straight or curved.

In another variant of the invention illustrated in FIG. 4c, at least two noise detectors 2a, 2b are installed, for example, in series respectively at two distinct predetermined distances L1, L2 of the obstacle 3.

It should be noted that each of the two detectors 2a, 2b delivers at its output, even in a noisy environment, a signal, for example, of the electrical and / or fluidic type, discriminating acoustic noise emanating from the obstacle 3. However, to avoid a priori any possible disturbances of the good functioning of the detector 2, for example, of sound and / or electromagnetic nature coming from the surrounding medium, it is possible to isolate at least one of the two detectors 2a, 2b using, for example, example, a sound insulator or a Faraday cage. Moreover, to minimize possible risks of noise pollution, at least one of the two detectors 2a, 2b can be placed in the environment to compensate for any influence of the surrounding noise on the proper functioning of the detector 2.

Figures 4-6 show enlarged views of the UU portion of the conduit 1 illustrating several embodiments of the invention. The duct 1 is formed by a wall 11 with the outer face 12 of diameter D opposite the inner face 13 of diameter d, the latter being oriented towards the preferred axis of the duct 1, for example, its axis of symmetry AB. The wall 11 is of a thickness μ such that μ = (D-d) / 2. The GS multiphase fluid is flowing inside 14 of the duct 1 in the direction of the arrow AB (from left to right in Figure 4 and 6). As shown in Figure 5, the UU portion of the duct 1 is cylindrical in shape of revolution. However this configuration is in no way limiting. In other words, the section of the duct 1 may have any closed profile, for example in the form of an oval, a rectangle, a trapezium, etc.

As shown in Figures 3-6, the portion 31 of the obstacle 3 extending along the preferred direction AB of the flow over the predetermined length LO is connected, for example integrally, with the wall 11 of conduit 1 with a segment 33. The latter is substantially parallel to the axis AZ which extends perpendicular to the preferred axis AB of the conduit 1 (Figure 4a). Thus, the segment 33 forms with the portion 31 of the obstacle 3 an angle β such that β = 90 °. In another embodiment of the invention, the segment 33 can be inclined relative to the portion 31 of the obstacle 3 so that 0 ° <β <180 °, β ≠ 90 °. Figure 4c illustrates the case with the angle β obtuse.

Similarly, angles φ, γ defining the positioning of the segment 33 with respect to the inner face 13 of the duct 1 respectively in a ZAB plane and in another plane perpendicular to the ZAB plane are such that: 0 ° <φ <180 ° ( Fig. 4e) and 0 ° <γ <180 ° (Fig. 5a), the angles φ, γ being also limited by the wall 11 of the duct 1. An intersection zone of the segment 33 with the portion 31 may be curved (Figures 3, 4a, 4d) or not (Figures 4b, 4c).

The portion 31 may have a flattened shape (Figures 3, 4a-d, 5-6), that is to say, substantially two-dimensional, or not (three-dimensional portion in section referenced 310, Figure 4e). Similarly, the segment 33 may have a flattened shape (FIGS. 3-6) or not (in the case of the three-dimensional segment 33 not shown in the figures).

In another variant of the invention, the segment 33 may have a substantially unidirectional shape, for example that of a thin rod.

It should be noted that the portion 31 and / or the segment 33 may include grooves, recesses, openings, etc. further disrupting the flow of GS multiphase flow. This makes it possible to control even more finely the number of eddies around and / or downstream of the obstacle 3 with respect to the direction AB of the flow, so as to obtain the level of discriminant noise by the detector 2 even for flows multiphasic GS weakly charged with solid particles S.

In the case of the three-dimensional portion 310 (Figure 4e), the latter may be full or have at least one chamber 311, said resonance. The box 311 may be made of homogeneous material or composite. The box 311 may in turn be hollow or at least partially filled by one or more predetermined loads, for example by hollow balls. The filling material of the well 311 and / or the shape of the predetermined load is chosen to amplify and / or adjust the acoustic emissions emitted by the obstacle 3 following the impacts of the solid particles S. Indeed, the size of the box 311 and / or the rate of its filling by the load determining the resonance frequency of the obstacle 3, can vary the carrier frequency representative of the impacts of the solid particles Against the obstacle 3. Of course, the segment 33 can also be three-dimensional and be arranged in the form of a box, for example cylindrical.

In another embodiment of the invention, the segment 33 and / or the portion 31 may be formed by a "curved plane", for example, by at least one fragment of a helical blade made from a sheet stainless steel (not shown in the figures). This is a particular geometry that can be described as "two-and-a-half (2.5D)", unlike the forms previously mentioned at one (ID), two (2D) or three (3D) dimensions. Indeed, while retaining its three-dimensional appearance on a large scale, that is to say, in its entirety, the blade is presented as a flat piece and flat on a small scale, that is to say, to the Scale of at least one predetermined vortex of the flow GS in the duct 1. With the obstacle 3 comprising at least one form 2.5D such that the blade, it is possible to disturb, predictably, the multiphase flow in the duct 1 in order to regulate the formation, the number and the intensity of the swirling lines enveloping the obstacle 3 and, consequently, the number and the intensity of the impacts of the particles S typing, for example, in the blade.

In an alternative embodiment of the invention, the obstacle 3 is formed by at least one lamella, of helical preference. The latter may be metallic, for example, stainless steel.

The obstacle 3 formed by the portion 31 and the segment 33, and in particular the obstacle formed by the metal strip, can be made in one piece or not. In the latter case, the elements 31, 33 forming the obstacle 3 can be secured, for example, using a weld.

The metal strip may be welded or fixed to the conduit 1 by mechanical clamping. In the case of mechanical clamping, it is advantageous to change the lamella without disassembling the sleeve 15 or adjust the height H (that is to say, the length H of the segment 33) of the lamella determining its penetration inside 14 of the duct 1 (FIG. 4b) as a function, for example, of the rate of the solid phase S in the multiphasic fluid GS, of the flow velocity in the duct 1 etc.

As shown in Figures 4, 5b, 5c, 6, the obstacle 3 is extended through the wall 11 of the duct 1 integrally with the duct 1 and forms a lug 32 on the outer face 12 of the duct 1.

As mentioned above, the obstacle 3 can comprise means for adjusting the length H of the segment 33 and / or the pin 32 and / or their inclination with respect to at least one of the two axes AB and / or AZ and / or the inner face 13 of the duct 1 (angles φ, γ). This advantageously allows to regulate the positioning of the portion 31 relative to the preferred axis AB of the conduit 1, for example, as shown in Figure 4b: Ha <Hb for the two portions 31a and 31b installed in series.

The detector 2 may be placed downstream (FIG. 4a) or upstream (not shown in the figures) of the portion 31 of the obstacle 3 and the lug 32 with respect to the direction AB of the flow GS in the duct 1. The noise detector 2 can also be arranged on the lug 32 (FIG. 4b, 4d, 6 ), the detector 2 with the pin 32 thus forming a unit of measurement. In this case, the noise is transmitted from the obstacle 3 to the sensor via the lug without the intermediary of the body of the duct 1. This configuration is particularly suitable for ducts 1 made of materials that absorb acoustic emissions, for example, from non-combustible materials. metal (plastic, glass). Finally, the device according to the invention can also comprise at least two detectors 2 of which a first detector is disposed on the lug 32 and a second detector is arranged, for example, on the bracket 20 or directly on the outer face 12 of the leads 1.

At least two measuring units can be installed in parallel with respect to the preferred direction AB of the GS flow, with obstacle acoustic properties 3 which may be different (shape, nature of manufacturing material, thickness, etc.). FIG. 5c illustrates this case with two obstacles 3a and 3b arranged in parallel (the respective noise detectors are not shown).

In another variant of the invention illustrated in FIG. 4b, at least two measurement units are installed in series with respect to the preferred direction AB of the flow GS. As shown in FIG. 4b, each portion 31a, 31b may have, for example, its own predetermined length (LOa ≠ LOb) extending along the preferred direction AB of the flow and / or its own thickness, etc. In another variant of the invention, a means selectively absorbing friction noise such as a rubber seal, is arranged between the friction noise detector 2 and the duct 1 (FIG. 3). Similarly, an absorbing means 21 can be added between the detector 2 and the pin 32 (Figure 6) or between the detector 2 and the bracket 20 (Figure 4a, 4e).

The operation of the measuring device according to the invention is illustrated with the aid of an example in FIG. 6. The solid particles S represented by dotted double-line arrows and issuing from the multiphase flow GS, firstly impact the segment 33 of the obstacle 3 in the form of the metal strip in this example. These first impacts are shown diagrammatically in FIG. 6 using the explosions referenced i ₀ . Then, swirling lines are created around the portion 31 of the obstacle 3. These vortices are shown schematically in Figure 6 using the curved arrows referenced Ti to T ₅ double dashed line. To avoid an overload of Figure 6, a vortex drag downstream of the obstacle 3 with respect to the direction of the flow AB, is not shown.

After having first impacted the segment 33 of the obstacle 3, at least part of the solid particles S is driven along the portion 31 by the vortices Ti to T ₅ by rubbing the obstacle 3 and, in particular, its portion 31 In addition, at least the particles S again hit the obstacle 3 and, in particular, its portion 31. These "second" impacts are shown schematically in Figure 6 using the explosions referenced i _τ . This multiplicity of impacts produced by the same particle S amplifies the number of acoustic emissions and, therefore, the friction noise sensed by the detector 2. The latter then generates at its output the signal proportional to the friction noise and, therefore, the flow rate of the powder S in the duct 1. The management equipment 6 receiving at its input the signal from the detector 2, pilot, using the control means, the fan 5 and / or the worm machine 4 so as, for example, to maintain the constant predetermined concentration of the reagent S in the multiphase flow GS upstream of the reactor R.

It should also be noted that the portion 31 of the obstacle 3 undergoes vibrations induced by the vortices T ₁ to T ₅ .

In summary, the friction noise sensed by the detector 2 can result from the different excitations of the obstacle 3 following, for example:

Local movements of the solid particles S substantially tangential with respect to the portion 31 producing the friction proper,

Local inclined or even perpendicular movements of the solid particles S with respect to the portion 31, resulting from their impacts against the portion 31,

• a vibratory movement of the portion 31 in its entirety induced by the vortices Ti to T ₅ .

Moreover, the vortex drag downstream of the obstacle 3 (not shown in FIG. 6) creates a noise called turbulent flow. The latter can be used to calibrate the detector 2 and / or to verify that it is functioning independently of the presence of the particles S in the multiphase flow GS. The vortex drag also amplifies the local motions of S particles downstream of obstacle 3 by favoring and the new impacts of the particles S against the inner face 13 of the duct 1 regardless of the geometry of the duct 1 and, in particular for the straight portions of the duct 1.

It should be noted that the parameters characterizing the friction noise such as its frequency and intensity can be regulated by the installer of the device according to the invention in the conduit 1 and / or by the operator. For example, it is possible to optimize the speed of the multiphase flow GS, its composition, the diameter of the duct 1, the number of obstacles 3 reported in the duct 1, the shape of the obstacle 3, its positioning in the duct 1 , its manufacturing material, its thickness, etc., without, however, slowing down the flow velocity because such obstacles 3, the dimensions of which are exaggerated in the figures, do not create a great deal of pressure drop.

The measuring range of the device according to the invention can be easily modified, for example, by the installer, so as to adjust, if necessary, a measurement scale of the device as a function, for example, of the different flow regimes. GS multiphase flow in the duct 1 and / or, inter alia, an increase and / or decrease in the concentration of the solid phase S in the GS multiphase flow.

Such a modification of the measuring range can be carried out using, for example, at least two noise detectors 2a, 2b installed on the brackets 20 in series respectively at two predetermined distances L1, L2 distinct from the obstacle 3 such that L1 <L2 (FIG. 4c). Once the detector is closer to the obstacle 3 (detector 2a, FIG. 4c) saturated (i.e. say, the signal at its output is no longer representative of the acoustic emissions emitted by the obstacle 3 and which are becoming more intense as the concentration of the solid phase S increases in the multiphase flow. GS), the other detector farthest from the obstacle 3 (detector 2b, FIG. 4c) takes over. This ability of the detector 2b (FIG. 4c) furthest from measuring the high flows of the solid phase S in the multiphase flow GS is obtained by attenuation of the friction noise at the input of the detector 2b (FIG. 4c). further. This attenuation can be achieved by one or more means, for example, by means 21 selectively absorbing the acoustic noise emanating from the obstacle 3, which can be, for example, the rubber seal (not shown in FIG. 4c) arranged between the other detector 2b and the bracket 20. Similarly, the friction noise necessarily traversing the distance L2 before reaching the furthest detector 2b, can also be attenuated by a specific material of the duct 1, for example by the conduit 1 comprising the plastic sleeve 15 (not shown in FIG. 4c) selectively absorbing the acoustic noise emanating from the obstacle 3.

The measuring range of the device according to the invention can also be easily modified using at least two measurement units, for example, installed in series with respect to the preferred direction AB of the flow GS (both units of measurement being referenced respectively (2a, 32a, 33a, 31a) and (2b, 21, 32b, 33b, 31b) in the example of Figure 4b). As schematically shown in FIG. 4b, each measurement unit can be provided with the obstacle 3 which is proper to him. However, as already mentioned above, the technical characteristics such as the shape of the obstacle 3, its height H determining its penetration into the interior 14 of the duct 1, its length LO, its thickness, etc. can alter the sensitivity of the unit of measurement to the impacts and / or vibrations induced by the multiphase flow GS, and therefore can modify, among other things, the measuring range of the unit of measurement. In other words, it should be understood that it is possible to optimize the technical characteristics of each of the two measurement units so that they can amplify and / or absorb differently the friction noise captured. Thus, when the extent of measurement of one of the two measurement units, for example that referenced (2a, 32a, 33a, 31a) in FIG. 4b, is no longer sufficient, that is to say the signal at the output of this measurement unit is no longer representative of the acoustic emissions emitted by the obstacle 3 (for example, too intense or too weak depending on whether the concentration of the solid phase S in the multiphasic stream GS is respectively higher or lower than a predetermined threshold value), it is the other unit of measurement, for example, that referenced (2b, 21, 32b, 33b, 31b) in Figure 4b and whose technical characteristics are precisely optimized to said concentration of the solid phase S in the multiphase flow GS, which takes over.

It should be understood that at least one or more of the above-mentioned means in connection with the modification of the measuring range of the device according to the invention can also be used to modify, for example, by the installer, the device resolution according to the invention so as to adjust it, if necessary, as a function, for example, of the different flow regimes of the multiphase flow GS in the duct 1 and / or, inter alia, the rise and / or fall the concentration of the solid phase S in the GS multiphase flow. The examples illustrating how such a modification of the measurement resolution of the device according to the invention can be made are not described here because they are similar to those, extensively discussed above, relating to the modification of the measuring range.

Claims

1. Device for measuring the flow rate of at least a first (S) of the constituents of a multiphase fluid (GS) in axial flow in a pipe (1) having a preferred axis (AB) by measuring a friction noise generated by the first component (S) of the multiphasic fluid

(GS), the measuring device comprising a non-intrusive noise detector (2) connected to an outer face (12) of the duct (1), at least one obstacle (3) attached to the inside (14) of the duct ( 1) and formed by at least one metal strip having at least one portion (31) extending axially in the conduit (1) and at least one segment (33) connecting the portion (31) with the conduit (1), characterized in that the portion (31) forms with the segment (33) in a plane (ZAB) comprising the axis (AB) a predetermined non-zero angle (β).

2. Measuring device according to claim 1, characterized in that the segment (33) has a flattened shape in a plane perpendicular to the axis (AB).

3. Measuring device according to claim 1 or 2, characterized in that the portion (31) and the segment (33) have a curved intersection area.

4. Measuring device according to any one of claims 1 to 3, characterized in that at least one of: (a) segment (33); (b) portion (31) is formed by at least one fragment of a blade.

5. Measuring device according to any one of the preceding claims, characterized in that the obstacle (3) cooperating with the flow of the multiphase fluid (GS) in the duct (1) generates the friction noise at least in a high frequency domain, as between preferably about 75 kHz and about 175 kHz.

6. Measuring device according to any one of the preceding claims, characterized in that it comprises:

At least one means for regulating (5) a gas phase (G) of the multiphase fluid (GS) flowing in the pipe (1),

At least one means for regulating (4) a solid phase (S) of the multiphase fluid (GS) flowing in the pipe (1),

At least one management equipment (6) linked by at least one electrical and / or fluid link with the detector

(3) noise and with at least one of the control means (4, 5) of the multiphasic fluid (GS) flowing in the conduit (1).

7. Measuring device according to any one of the preceding claims, characterized in that a selectively absorbent seal (21) friction noise is arranged between the noise detector (2) and the duct (1).

8. Measuring device according to any one of the preceding claims, characterized in that it comprises at least two noise detectors (2) respectively installed at two distinct predetermined distances (L1, L2) of the obstacle (3).

9. Measuring device according to any one of the preceding claims, characterized in that the obstacle (3) is extended through a wall (11) of the duct (1) integrally with the duct (1), forming a pin ( 32) on the outer face (12) of the duct (1).

Measuring device according to claim 9, characterized in that the noise detector (2) is disposed on the lug (32), the sensor (2) with the lug (32) forming a unit of measurement.

11. Measuring device according to claim 10, characterized in that it comprises at least two measurement units installed according to one of the configurations chosen from the following configurations with respect to the axis

(AB) of the duct (1): (a) in parallel; (b) in series.

12. Measuring device according to any one of the preceding claims, characterized in that the obstacle (3) comprises means for adjusting its positioning inside (14) of the conduit (1).