Test bench for carrying out erosion and / or corrosion tests

Abstract

The invention relates to a test bench (1) for carrying out corrosion and / or erosion tests, the test bench comprising: • - a mixing reactor (2) configured to mix new erosive particles (7) from a second inlet (22) and a corrosive fluid from a first inlet (21) so as to obtain a stream of a homogeneous particle-fluid mixture (8); • - a test chamber (3) configured to accommodate and test at least one sample (6) under the effect of the mixture (8) from the outlet (11) of the reactor (2) flowing from the inlet (12) to the outlet (13a, 13b) of the chamber (3); • - a decantation system (4) configured to decant the mixture (8) from the outlet (13a, 13b) so as to separate the erosive particles used for carrying out the test and the corrosive fluid; • - a recirculation network (5) configured to convey the corrosive fluid from the outlet (27) of the system (4) to the first inlet (21).

Description

Test bench for carrying out erosion and / or corrosion tests

[0001] The invention relates to a test bench for carrying out erosion and / or corrosion tests. STATE OF THE ART

[0002] Erosion refers to the progressive wear of a material under the effect of a high-speed flow of fluid and / or solid particles. Corrosion refers to the progressive deterioration of a material caused by a chemical and / or electrochemical reaction with the environment. The corrosion phenomenon is a relatively well-known and predictable process. In contrast, the erosion phenomenon is not as well understood. Attempts to model the latter in very specific cases remain few. The evolution of a material undergoing both corrosion and erosion phenomena is even more difficult to predict and requires the implementation of experimental tests.For example, such a situation of simultaneous corrosion and erosion is frequently encountered inside centrifugal pumps, for example centrifugal pumps used by the chemical, petrochemical or hydrometallurgical industries, and explains their relatively rapid degradation. As another example, this dual phenomenon is encountered in centrifugal pumps in the phosphate mining industries, said pumps being able to circulate mixtures comprising phosphoric acid and phosphogypsum particles.

[0003] Test benches are therefore used to test the resistance of materials (e.g., materials constituting components of the aforementioned centrifugal pumps) to erosion and corrosion simultaneously. The erosive and corrosive conditions created by such test benches accelerate the phenomenon of material degradation and facilitate its observation.

[0004] Slurry pot test benches consist of a test chamber, most often cylindrical in shape, closed by a lid. Before a test begins, the experimenter places samples of the materials to be tested, as well as a mixture comprising a liquid that may be corrosive, for example an acid, and erosive particles inside the test chamber.

[0005] At the beginning of the test, the samples are rotated in the test chamber so that they are exposed to the flow of the liquid-particle mixture. Hard particles erode the exposed sample surfaces under the effect of shocks. The rotation speed of the samples, the mass ratio of the liquid-particle mixture, the size of the erosive particles, the type of corrosive liquid, the duration of the test and the temperature are all parameters that the experimenter can vary to study their influence.

[0006] At the end of the test, the experimenter recovers the samples which he can analyze, in particular by measuring the loss of mass undergone by said samples or by observing their profilometry, for example by microscopy.

[0007] One of the main drawbacks of the previously described "slurry pot" type test benches lies in the progressive blunting of the erosive particles during the test. Indeed, the particles wear under the effect of shocks and their erosive action is therefore not constant over the entire duration of the test, but on the contrary decreases progressively. Such a decrease in the erosion rate during the test makes it difficult to interpret the results.

[0008] Another disadvantage of slurry pot test benches lies in the quality of homogenization of the liquid-particle mixture within the test chamber. Indeed, the mixture is homogenized by the experimenter only before its introduction into the test chamber and the start of the test. Since the particles tend to fall by gravity to the bottom of the test chamber, the mass ratio of the liquid-particle mixture varies locally over the height of the test chamber during the test, so that the mass ratio of the liquid-particle mixture to which the samples are locally subjected is different from that set globally by the experimenter for carrying out the test, thus distorting the measurement. A possible improvement of slurry pot test benches consists of adding a turbine in the test chamber to homogenize the particle-fluid mixture in the chamber also during the test duration.However, simulations of such test chambers show that this turbine alone does not completely avoid the problem. In addition, adding a turbine complicates the assembly of the test chamber. BRIEF DESCRIPTION OF THE INVENTION

[0009] An aim of the invention is to design a test bench for erosion / corrosion tests of materials which generates an erosive action on the samples tested which is controlled and constant throughout the test chamber and throughout the duration of the test, so as to obtain reproducible results which are easier to interpret.

[0010] For this purpose, the invention proposes a test bench for carrying out corrosion and / or erosion tests comprising:- a mixing reactor comprising a first inlet, a second inlet and an outlet, the first inlet of the mixing reactor being supplied with a flow of a corrosive fluid and the second inlet being supplied with new erosive particles, the mixing reactor being configured to mix the new erosive particles and the corrosive fluid, so as to obtain, at the outlet of the mixing reactor, a circulation flow of a homogeneous particle-fluid mixture,- a test chamber comprising an inlet fluidically connected to the outlet of the mixing reactor and an outlet,the test chamber being configured to accommodate at least one sample and to carry out the corrosion and / or erosion test of the at least one sample under the impact of the homogeneous particle-fluid mixture from the mixing reactor circulating from the inlet of the test chamber to the outlet of said chamber,- a decantation system comprising an inlet fluidically connected to the outlet of the test chamber and an outlet, the decantation system being configured to decant the homogeneous particle-fluid mixture from the test chamber so as to separate the erosive particles used to carry out the test and the corrosive fluid from said mixture,- a fluid recycling network configured to convey the corrosive fluid separated from the erosive particles used to carry out the test from the outlet of the decantation system to the first inlet of the mixing reactor,so that the corrosive fluid stream feeding the mixing reactor includes the recycled corrosive fluid.,

[0011] The test bench according to the invention generates a continuous flow of the liquid-particle mixture: new erosive particles, whose erosive characteristics are known, are mixed with the corrosive fluid in the mixing reactor before reaching the test chamber where they are used to carry out the test. The new particles become blunt under the effect of impacts with the samples and / or with the walls of the test chamber. However, under the effect of the flow, they are evacuated to the outlet of the test chamber: the decantation system then makes it possible to eliminate them while recycling the corrosive fluid. This recycled fluid is remixed with new erosive particles upon its return to the mixing reactor before returning to the test chamber.Thus, the test chamber is constantly supplied with non-blunt erosive particles, which guarantees a constant erosion rate throughout the duration of the test under the conditions chosen for the test.

[0012] Furthermore, the continuous flow of the liquid-particle mixture between the mixing reactor and the settling system through the test chamber ensures a smoother and more homogeneous liquid-particle mixture between the top and the bottom of the test chamber than in the state-of-the-art "slurry pot" configuration where only the rotation of the sample holder and possible additional turbines ensure the homogenization of the mixture.

[0013] According to other optional features of the invention taken alone or in combination when technically possible:

[0014] - the test chamber is located below the mixing reactor and above the settling system, the outlet of the mixing reactor being located in a lower part of said mixing reactor, the inlet of the test chamber being located in an upper part of the test chamber and the outlet of the test chamber being located in a lower part of the test chamber;

[0015] - the test bench further comprises a first valve adapted to control the flow rate of the circulation flow of the homogeneous particle-fluid mixture entering the test chamber and a second valve adapted to control the flow rate of the circulation flow of the homogeneous particle-fluid mixture leaving the test chamber, so as to keep the level of the particle-fluid mixture constant in the test chamber;

[0016] - the test bench further comprises a reservoir of new erosive particles arranged so as to supply the second inlet of the mixing reactor, preferably located above the mixing reactor;

[0017] - the test bench further comprises a third variable opening valve for controlling the flow rate of a stream of new erosive particles conveyed from the new erosive particle reservoir to the second inlet of the mixing reactor;

[0018] - the test bench further comprises a peristaltic pump connected to the recycling network, the peristaltic pump being adapted to pump the corrosive fluid separated from the erosive particles used to carry out the test from the outlet of the decantation system to the first inlet of the mixing reactor, the peristaltic pump being further adapted to control the flow rate of the corrosive fluid supplying the first inlet of the mixing reactor;

[0019] - the test chamber comprises a bottom wall, a top wall and at least one side wall extending between the bottom wall and the top wall, the top wall forming a cover of the test chamber and the outlet of the test chamber being located in the bottom wall of said test chamber;

[0020] - the at least one side wall of the test chamber comprises PVC and / or the bottom wall and the top wall comprise polyamide;

[0021] - at least one side wall of the test chamber is separable from the bottom wall and the top wall;

[0022] - the test chamber further comprises baffles arranged on the at least one side wall of the test chamber so as to limit the formation of turbulent flows in the homogeneous particle-fluid mixture in the test chamber;

[0023] - the test chamber further comprises a sample holder, the sample holder being configured to be assembled with the at least one sample, the sample holder being further configured to be rotated relative to the lower wall of the test chamber around an axis of rotation of the sample holder, said axis of rotation being perpendicular to the lower wall of the test chamber and passing through the center of gravity of the sample holder;

[0024] - the test bench further comprises a first variable speed motor, the first variable speed motor being configured to rotate the sample holder around the rotation axis of the sample holder at a rotation speed chosen for carrying out the test;

[0025] - the entrance to the test chamber is located in the upper wall of the test chamber, at the intersection between said upper wall and the axis of rotation of the sample holder;

[0026] - the mixing reactor comprises a turbine and a second variable speed motor, the second variable speed motor being configured to drive the turbine in rotation, the mixing of the new erosive particles with the corrosive fluid being carried out under the effect of the rotation of said turbine;

[0027] - the mixing reactor comprises a heating system configured to heat the corrosive fluid during the mixing of said fluid with the new erosive particles, so that the homogeneous particle-fluid mixture at the outlet of the mixing reactor is brought to a temperature chosen for carrying out the test;

[0028] - the mixing reactor comprises an inner wall and an outer wall, the inner wall and the outer wall forming a double wall of the mixing reactor, and wherein the heating system comprises a heat transfer fluid which circulates between the inner wall and the outer wall, so that the heating of the corrosive fluid in the mixing reactor is carried out by heat transfer between the heat transfer fluid and the corrosive fluid through the inner wall;

[0029] - the settling system comprises a first settling tank comprising an inlet forming the inlet of the settling system and a second settling tank comprising an outlet forming the outlet of the settling system, the first tank further comprising an outlet fluidically connected to an inlet of the second tank, the outlet of the first tank being located in an upper part of said first tank), so that only an upper part of the particle-fluid mixture settled in the first tank flows into the second tank, the outlet of the settling system being located in an upper part of the second tank, so as to collect only the corrosive fluid separated from the erosive particles used to carry out the test, said particles remaining at the bottom of the first tank and the second tank;

[0030] - the first settling tank is located above the second settling tank. BRIEF DESCRIPTION OF THE FIGURES

[0031] Other characteristics and advantages of the invention will emerge from the detailed description which follows, with reference to the appended drawings, in which:

[0032] - represents an embodiment of a test bench for carrying out erosion and / or corrosion tests according to the invention comprising a mixing reactor, a test chamber, a settling system and a recycling network.

[0033] - Figure 2 represents the interior of the test chamber with sample holder and baffles according to a particular embodiment of the invention.

[0034] For readability reasons, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION OF EMBODIMENTS

[0035] The invention relates to a test bench 1 for carrying out corrosion and / or erosion resistance tests on various materials. In particular, the test bench 1 makes it possible to subject one or more samples of the material(s) to be tested to a flow exhibiting an erosive and / or corrosive action mimicking the operating conditions of centrifugal pumps in the chemical, metallurgical and / or mining industries. Before and after the test, the samples can be analyzed (for example by profilometry and / or by mass loss) so as to classify the materials constituting said samples according to their resistance to corrosion and / or erosion under the simulated conditions and thus determine which of the materials is most suitable for the operating conditions of the centrifugal pump.

[0036] Furthermore, test bench 1 can be used to study erosive and / or corrosive damage modes and thus allow the experimenter to model said damage modes and guide the process of developing new materials.

[0037] With reference to the, the test bench 1 according to the invention comprises a mixing reactor 2, a test chamber 3, a settling system 4 and a fluid recycling network 5.

[0038] Prior to implementing a corrosion and / or erosion test of at least one sample 6 on said test bench 1, the experimenter positions the sample 6 in the test chamber 3. During the test, the mixing reactor 2 continuously homogenizes a corrosive fluid with new erosive particles 7. A circulation flow of said homogenized mixture 8 circulates from the mixing reactor through the test chamber 3 into the settling system 4. Thus, the erosive particles which, under the effect of impacts with the walls of the test chamber 3 and / or the sample(s) 6, have lost their sharpness, are carried along by the circulation flow and systematically eliminated in the settling system 4, so that each sample 6 is impacted during the entire duration of the test only by new erosive particles 7.This mode of operation in an open reactor rather than a closed reactor makes it possible to simulate an erosive action on the samples which is constant and controlled throughout the duration of the test.

[0039] The recycling network 5 allows for the recovery, at the level of the decantation system 4, of the corrosive fluid separated from the spent erosive particles to supply the mixing reactor 2 with corrosive fluid. Thus, unlike the erosive particles, the corrosive fluid circulates continuously in a closed circuit inside the test bench 1 between the mixing reactor 2, the test chamber 3, the decantation system 4 and the recycling network 5. Such recycling allows a smaller quantity of fluid to be consumed. Furthermore, in the case where the mixing reactor 2 comprises a heating system, as described below, allowing the test to be carried out at a set temperature of the homogeneous particle-fluid mixture 8, the recycling ensures better control of said temperature than the constant introduction of cold corrosive fluid. Indeed, heating the cold fluid would require a lot of time and energy.

[0040] In the remainder of this presentation, a method of producing each element included in the test bench 1 is detailed in more detail. Test Chamber 3

[0041] The test chamber 3 is configured to accommodate the sample(s) 6 and to carry out the corrosion and / or erosion test of the sample(s) 6 under the impact of an erosive and / or corrosive flow of the homogeneous particle-fluid mixture 8. For this purpose, the test chamber 3 may comprise a sample holder 9 configured to be assembled with each sample 6.

[0042] During a test, the sample holder 9 is rotated relative to the walls of the test chamber 3 around an axis of rotation (X) of the sample holder 9, said axis (X) passing through the center of gravity of the sample holder 9, for example using a first variable speed motor 10 and an elastic coupling 33, at a rotation speed chosen for carrying out the test.

[0043] The rotation of the sample holder 9 rotates each sample 6 in the particle-fluid mixture 8, which makes it possible to simulate the movement of an erosive and / or corrosive flow impacting the sample 6. The rotation speed of the sample holder 9, therefore corresponding to a speed of the corrosive and / or erosive flow impacting the sample, is therefore an interesting parameter to control and / or test on the test bench for the experimenter: the greater the speed of the corrosive and / or erosive flow, the faster the material erodes and / or corrodes. Preferably, the rotation speed of the sample holder 9 can be controlled, so that the speed of the corrosive and / or erosive flow impacting the sample is chosen to be between 0 m / s and 50 m / s.The rotation speed of the sample holder 9 is high compared to the speed of the circulation flow of the homogeneous particle-fluid mixture 8, so that the speed of the erosive and / or corrosive flow impacting the sample 6 is generally that of the rotation speed of the sample holder 9 (without impact of the circulation flow of the particle-fluid mixture 8 through the test chamber).

[0044] The test chamber 3 further comprises an inlet 12 in fluid connection with an outlet 11 of the mixing reactor and an outlet 13 in fluid connection with an inlet 14 of the settling system 4. During a test, the circulation flow of the homogeneous particle-fluid mixture 8 continuously leaves the mixing reactor 2 through the outlet 11 of said reactor 2 to feed the inlet 12 of the test chamber 6. The flow rate of said circulation flow not exceeding 50 mL / s, the speed of the circulation flow of the homogeneous particle-fluid mixture 8 is generally negligible compared to the rotation speed of the sample holder 9. In the test chamber 3, the circulation flow of the homogeneous particle-fluid mixture 8 circulates from the inlet 12 of the test chamber to the outlet 13 of said chamber 3, where it is drained to the inlet 14 of the settling system 4.

[0045] Optionally, the test bench 1 further comprises a first valve 15 adapted to control the flow rate of the homogeneous particle-fluid mixture 8 entering the test chamber 3 and a second valve 16 adapted to control the flow rate of the circulation flow of the homogeneous particle-fluid mixture 8 leaving the test chamber 3, so as to keep the level of the particle-fluid mixture 8 in the test chamber 3 constant throughout the duration of the test. The level of the particle-fluid mixture 8 in the test chamber 3 is chosen so as to keep the sample holder 9 completely submerged.

[0046] Preferably, the test chamber 3 is located below the mixing reactor 2 and above the settling system 4. According to this embodiment, the inlet 12 of the test chamber 3 is located in an upper part of the test chamber 3 and the outlet 13 of the test chamber 3 is located in a lower part of the test chamber 3, so that the circulation of the circulation flow of the homogeneous particle-fluid mixture 8 in the test chamber 3 is facilitated by the action of gravity, so that a pump is not necessary to ensure the circulation of the circulation flow of the homogeneous particle-fluid mixture 8. According to this embodiment, the outlet 11 of the mixing reactor 2 is advantageously located in a lower part of said mixing reactor 2.

[0047] More specifically, the test chamber 3 may comprise a bottom wall 17, a top wall 18 and at least one side wall 19 which extends between the bottom wall 17 and the top wall 18 (for example a generally cylindrical shape), the bottom wall 17, the top wall 18 and the side wall 19 defining an interior volume in which the homogeneous particle-fluid mixture 8 temporarily resides, the level of the homogeneous particle-fluid mixture 8 in said volume being preferably kept constant throughout the duration of the test. The sample holder 9 is arranged in the interior volume defined by the bottom wall 17, the top wall 18 and the at least one side wall 19, so that the axis of rotation (X) of the sample holder 19 is perpendicular to the bottom wall 17 of the test chamber 3.The upper wall 18 can form a cover allowing the at least one sample 6 to be placed in the test chamber 3 before the start of the test and to be removed at the end of the test.

[0048] The inlet of the test chamber 3 may be located in the upper wall 18 of the test chamber, at the intersection between said upper wall 18 and the axis of rotation (X) of the sample holder 9, and the outlet 13 of the test chamber 3 in the lower wall 17 of the test chamber 3. According to this embodiment, the sample holder 9 may advantageously comprise a conical-shaped cap configured to fit onto an upper surface of the sample holder perpendicular to the axis of rotation (X), the apex of the cone, when the cap is fitted, being located on the axis of rotation (X) of the sample holder (see the representation of the sample holder 9 on the). In this way, the particle-fluid mixture 8 is introduced directly into the center of the upper cone of the sample holder 9, which makes it possible, in the case of large / heavy particles, to distribute said particles uniformly in the test chamber 3.Optionally, the outlet 13 of the test chamber 3 comprises two drain pipes 13a and 13b. Increasing the number of drain pipes advantageously makes it possible to avoid the appearance of areas in the test chamber 3 in which the particles would remain blocked and would not be properly drained.

[0049] Optionally, the at least one side wall 19 of the test chamber 3 is separable from the lower wall 17 and the upper wall 18, which makes it possible to change said wall 19 when it is worn (eroded and / or corroded) under the impact of the homogeneous particle-fluid mixture 8 after too many tests.

[0050] The high-speed rotation of the sample 6 may cause the formation of turbulent flows, or vortices, in the homogeneous particle-fluid mixture 8 when it is in the test chamber 3. Advantageously, the test chamber 3 may comprise baffles 20 arranged on the side wall 19 of the test chamber 3 so as to limit the formation of said turbulent flows. For example, the test chamber 3 may comprise two (see FIG. 2 which represents the interior of the test chamber 3), respectively four baffles, distributed so as to guarantee the symmetry of the test chamber 3 by rotation at 180°, respectively at 90°, by rotation around the axis of rotation (X) of the sample holder 9.According to a particular embodiment of the baffles 20, the baffles 20 are assembled on the upper wall 18 which forms a cover of the test chamber 3, so that when the test chamber 3 is closed, the baffles 20 are arranged on the side wall 19.

[0051] The side wall 19 of the test chamber 3 is made of one or more materials with high corrosion resistance, for example stainless steel, preferably 304 stainless steel or 316 stainless steel. The internal face of the side wall 19 (face located opposite the interior volume defined by the walls of the test chamber 3) may advantageously comprise elements, for example cylindrical components, made of polymers, for example PVC, rubber, polyamide or any other material which offers particular resistance to corrosion and which will thus effectively protect the internal face of the metal side wall 19. The lower wall 17 and the upper wall 18 comprise, for example, polyamide or any other corrosion-resistant material. In the case where the test chamber 3 comprises baffles 20, the baffles may also be made of polyamide or another corrosion-resistant material.

[0052] As an example of embodiment of the sample holder 9, the sample holder 9 may comprise, in addition to the upper surface, at least one lateral surface and one interior surface, such that the interior volume defined by the upper surface, the lateral surface and the lower surface is full of material. If it is full of material, the sample holder 9 advantageously makes it possible not to generate parasitic flows of the particle-fluid mixture 8 inside the sample holder 9 when said sample holder 9 is rotating about its axis of rotation (X) in the test chamber 3, immersed in the particle-fluid mixture 8.

[0053] As another example, the sample holder 9 may comprise a single lateral surface of revolution around the axis of rotation (X) of the sample holder 9, as well as at least two supports arranged on said lateral surface to each accommodate a sample. Advantageously, a first support and a second support among the at least two supports arranged on the lateral surface of the sample holder 9 may be configured so that, when the first sample and the second sample are fixed respectively on the first support and the second support, the main surface of each sample is oriented at a different respective angle relative to a plane perpendicular to the axis of rotation (X).Such a configuration of the supports allows the experimenter to study at least two different angles of impact of the erosive and / or corrosive flow on the samples of the materials to be studied during the same test, the other parameters being strictly identical. Indeed, the angle of impact of the erosive and / or corrosive flow is another interesting parameter in the study of erosion and / or corrosion phenomena. Mixing reactor 2

[0054] As mentioned previously, the mixing reactor 2 comprises an outlet 11 in fluid connection with the inlet 12 of the test chamber 3.

[0055] The mixing reactor 2 further comprises a first inlet 21 supplied with a flow of a corrosive fluid and a second inlet 22 supplied with a flow of new erosive particles 7. For example, the flow rate of the flow of the corrosive fluid supplying the first inlet 21 is less than 50 mL / s. For example again, the flow rate of the flow of new erosive particles 7 supplying the second inlet 22 may be between 0.1 g / s and 0.6 g / s. Controlling said flow rates makes it possible to control the erosion rate and the duration of the test. Thus, increasing the flow rates of the flow of the corrosive fluid and the flow of the new erosive particles advantageously makes it possible to increase the erosion rate and reduce the duration of the test. Beyond a threshold value of the flow rate of new erosive particles, the erosion rate decreases. The choice of flow rates must be adapted according to the equipment used, in particular the pipes and any pumps.The mixing reactor 2 is configured to mix the new erosive particles 7 coming from the second inlet 22 and the corrosive fluid coming from the first inlet 21, so as to obtain, at the outlet 11 of the mixing reactor 2, the circulation flow of a homogeneous particle-fluid mixture 8.

[0056] Thus, unlike the configuration of a "slurry pot", the homogenization of the particle-fluid mixture is implemented, in a test bench 1 according to the invention, not in the test chamber, but upstream of the test chamber in the mixing reactor 2.

[0057] Optionally, the second inlet 22 of the mixing reactor 2 is connected to a reservoir 23 comprising fresh erosive particles 7, so that the supply of fresh erosive particles 7 to the second inlet 22 is ensured by said reservoir 23. Before the start of the test, the experimenter can choose the size and shape of the particles that he wishes to use for the test, said size and said shape defining the erosive action of the particles, and place said particles in the reservoir 23. The particles will then be distributed to the mixing reactor 2 for the entire duration of the test without intervention by the experimenter.

[0058] Preferably, the reservoir 23 of new erosive particles 7 is located above the mixing reactor 2 and the second inlet 22 of the mixing reactor in an upper part of said mixture, so that the supply of new erosive particles to the mixing reactor 2 by the reservoir 23 comprising the new erosive particles 7 is facilitated by gravity, not requiring the use of a pump.

[0059] Optionally, a third variable opening valve 24 allows the experimenter to control the flow rate of the stream of new erosive particles 7 conveyed from the reservoir 23 of new erosive particles to the second inlet 22 of the mixing reactor 2.

[0060] For example, the homogenization of the corrosive fluid and the new erosive particles can be carried out in the mixing reactor 2 by a turbine of the mixing reactor and a second variable speed motor, the second variable speed motor being configured to drive the turbine in rotation, the mixing of the new erosive particles with the corrosive fluid being carried out under the effect of the rotation of said turbine. The homogenization of the corrosive fluid and the new erosive particles is more or less difficult depending on the flow rate of the new erosive particles and the size and / or mass of said particles. The use of the second variable speed motor therefore advantageously makes it possible to test on the test bench 1 several types of new erosive particles at several concentrations while maintaining good homogenization thanks to the adaptation of the rotation speed of the second motor to the chosen particles.The rotation speed of the second variable speed motor is for example between 0 rpm and 3000 rpm.

[0061] The mixing reactor 2 advantageously comprises a heating system 25 configured to heat the corrosive fluid during the mixing of said fluid with the new erosive particles 7, so that the homogeneous particle-fluid mixture 8 at the outlet of the mixing reactor 2 is brought to a temperature chosen for carrying out the test. Temperature is a parameter influencing the kinetics of erosion and / or corrosion phenomena. It is therefore very interesting for the experimenter to be able to control and / or study the influence of this parameter on the test bench 1.

[0062] According to a particular embodiment, the mixing reactor 2 comprises an inner wall and an outer wall (not shown in the), the inner wall and the outer wall forming a double wall of the mixing reactor 2. The heating system 25 then comprises a pump and a heat transfer fluid 26, for example water, the pump circulating the heat transfer fluid 26 between the inner wall and the outer wall, so that the heating of the corrosive fluid in the mixing reactor 2 is carried out by heat transfer between the heat transfer fluid 26 and the corrosive fluid through the inner wall.

[0063] Such an embodiment of the fluid heating is different from that implemented in the "slurry pots" of the state of the art where it is generally the test chamber which is heated. Heating the corrosive fluid by the mixing reactor 2 is a simple implementation solution given the wide availability of heating mixing reactors. Decanting system 4

[0064] As previously described, the decantation system 4 comprises an inlet 14 in fluid connection with the outlet 13 of the test chamber 3 which is supplied by the circulation flow of the homogeneous particle-fluid mixture 8 comprising the corrosive fluid and the erosive particles previously used to carry out the test in the test chamber 3.

[0065] The decantation system 4 is configured to decant said homogeneous particle-fluid mixture 8 from the test chamber 3 so as to separate the erosive particles 7 used to carry out the test and the corrosive fluid from said mixture 8, and thus allow the elimination of the used erosive particles and the recovery of the corrosive fluid by the recycling network 5.

[0066] For this purpose, the settling system 4 may comprise a settling tank comprising an inlet forming the inlet 14 of the settling system 4 and an outlet forming an outlet 27 of the settling system 4 (embodiment not shown). The erosive particles used to carry out the test are deposited at the bottom of the settling tank. The outlet of the settling system is located in an upper part of the settling tank, so as to collect only the supernatant corrosive fluid separated from the spent erosive particles.

[0067] Advantageously, the decanting system 4 may comprise a first decanting tank 28 comprising an inlet forming the inlet 14 of the decanting system 4 and a second decanting tank 29 comprising an outlet forming the outlet 27 of the decanting system (see). According to this embodiment of the decanting system 4, the first tank 28 further comprises an outlet 30 fluidically connected to an inlet 31 of the second tank 29, the outlet 30 of the first tank 28 being located in an upper part of said first tank 28, so that only an upper part of the particle-fluid mixture decanted in the first tank 28 flows into the second tank 29. Indeed, the particles being heavy, the upper part of the decanted particle-fluid mixture essentially comprises corrosive fluid.Similarly, the outlet 27 of the settling system 4, for example a slot, is located in an upper part of the second tank 29, so that only the liquid leaves the settling system 4. The use of a second settling tank in series with a first settling tank makes it possible to improve the separation between the corrosive liquid and the particles by carrying out a second settling phase. In particular, the use of two settling tanks makes it possible to better remove the particles. Recycling Network 5

[0068] The corrosive fluid recycling network 5 is configured to convey the corrosive fluid separated from the erosive particles used to carry out the test from the outlet 27 of the decantation system 4 to the first inlet 21 of the mixing reactor 2, so that the flow of corrosive fluid which feeds the mixing reactor 2 includes the recycled corrosive fluid.

[0069] A peristaltic pump 32 can advantageously be connected to the recycling network 5, the peristaltic pump 32 being adapted to pump the corrosive fluid separated from the erosive particles used to carry out the test from the outlet 27 of the decantation system 4 to the first inlet 21 of the mixing reactor 2, the peristaltic pump 32 being further adapted to control the flow rate of the corrosive fluid flow feeding the first inlet 21 of the mixing reactor 2.

[0070] Advantageously, the first settling tank is located above the second settling tank, so as to reduce the effort which must be provided by the peristaltic pump 32.

[0071] Controlling the flow rate of the corrosive fluid stream feeding the first inlet 21 of the mixing reactor 2 relative to the flow rate of the stream of new erosive particles 7 feeding the second inlet 22 of the mixing reactor 2 allows the experimenter to control the particle-to-fluid mass ratio of the homogeneous particle-fluid mixture 8 feeding the inlet 12 of the test chamber 3, which is another important parameter for the experimenter. The particle-to-fluid mass ratio is advantageously less than 30%. Above this particle concentration, the erosive action of the homogeneous particle-fluid mixture 8 artificially decreases due to the increase in the collision rate between the particles, said collisions dissipating part of the kinetic energy of the particles before impact with the samples.

[0072] The recycling network 5 is configured to protect the peristaltic pump from the erosive effect of the particles and to prevent the same, potentially blunt, particles from being used multiple times, which would lead to an uncontrolled decrease by the experimenter in the erosive action of the particle-fluid mixture. For this purpose, the recycling network 5 pumps the liquid into an upper part of the settling system 4.

Claims

Test bench (1) for carrying out corrosion and / or erosion tests comprising:- a mixing reactor (2) comprising a first inlet (21), a second inlet (22) and an outlet (11), the first inlet (21) of the mixing reactor (2) being supplied with a flow of a corrosive fluid and the second inlet (22) being supplied with new erosive particles (7), the mixing reactor (2) being configured to mix the new erosive particles (7) and the corrosive fluid, so as to obtain, at the outlet (11) of the mixing reactor (2), a circulation flow of a homogeneous particle-fluid mixture (8),- a test chamber (3) comprising an inlet (12) in fluid connection with the outlet (11) of the mixing reactor (2) and an outlet (13a, 13b),the test chamber (3) being configured to accommodate at least one sample (6) and to carry out the corrosion and / or erosion test of the at least one sample under the impact of the homogeneous particle-fluid mixture (8) from the mixing reactor (2) circulating from the inlet of the test chamber (12) to the outlet (13a, 13b) of said chamber (3), - a decantation system (4) comprising an inlet (14) in fluid connection with the outlet (13a, 13b) of the test chamber (3) and an outlet (27), the decantation system (4) being configured to decant the homogeneous particle-fluid mixture (8) from the test chamber (3) so as to separate the erosive particles used to carry out the test and the corrosive fluid from said mixture,- a fluid recycling network (5) configured to convey the corrosive fluid separated from the erosive particles used to carry out the test from the outlet (27) of the decantation system (4) to the first inlet (21) of the mixing reactor (2), so that the flow of corrosive fluid which feeds the mixing reactor (2) comprises the recycled corrosive fluid., Test bench (1) according to claim 1, wherein the test chamber (3) is located below the mixing reactor (2) and above the settling system (4), the outlet (11) of the mixing reactor (2) being located in a lower part of said mixing reactor (2), the inlet (12) of the test chamber (3) being located in an upper part of the test chamber (3) and the outlet (11) of the test chamber (3) being located in a lower part of the test chamber (3). Test bench (1) according to one of claims 1 or 2, further comprising a first valve (15) adapted to control the flow rate of the circulation flow of the homogeneous particle-fluid mixture (8) entering the test chamber (3) and a second valve (16) adapted to control the flow rate of the circulation flow of the homogeneous particle-fluid mixture (8) leaving the test chamber (3), so as to keep the level of the particle-fluid mixture (8) constant in the test chamber (3). Test bench (1) according to one of claims 1 to 3, further comprising a reservoir (23) of new erosive particles (7) arranged so as to supply the second inlet (22) of the mixing reactor (2), preferably located above the mixing reactor (2). Test bench (1) according to claim 4, further comprising a third variable opening valve (24) for controlling the flow rate of a stream of new erosive particles (7) conveyed from the reservoir (23) of new erosive particles (7) to the second inlet (22) of the mixing reactor (2). Test bench (1) according to one of claims 1 to 5, further comprising a peristaltic pump (32) connected to the recycling network (5), the peristaltic pump (32) being adapted to pump the corrosive fluid separated from the erosive particles used to carry out the test from the outlet (27) of the decantation system (4) to the first inlet (21) of the mixing reactor (2), the peristaltic pump (32) being further adapted to control the flow rate of the flow of corrosive fluid feeding the first inlet (21) of the mixing reactor (2). Test bench (1) according to one of claims 1 to 6, wherein the test chamber (3) comprises a bottom wall (17), a top wall (18) and at least one side wall (19) which extends between the bottom wall (17) and the top wall (18), the top wall (18) forming a cover of the test chamber (3) and the outlet (13) of the test chamber (3) being located in the bottom wall (17) of said test chamber (3). Test bench (1) according to claim 7, wherein the at least one side wall (19) of the test chamber (3) comprises PVC and / or the bottom wall (17) and the top wall (18) comprise polyamide. Test bench (1) according to one of claims 7 or 8, wherein the at least one side wall (19) of the test chamber (3) is separable from the bottom wall (17) and the top wall (18). Test bench (1) according to one of claims 7 to 9, wherein the test chamber (3) further comprises baffles (20) arranged on the at least one side wall (19) of the test chamber (3) so as to limit the formation of turbulent flows in the homogeneous particle-fluid mixture (8) in the test chamber (3). Test bench (1) according to one of claims 7 to 10, wherein the test chamber (3) further comprises a sample holder (9), the sample holder (9) being configured to be assembled with the at least one sample (6), the sample holder (9) being further configured to be rotated relative to the lower wall (17) of the test chamber (3) around an axis of rotation (X) of the sample holder (9), said axis of rotation (X) being perpendicular to the lower wall (17) of the test chamber (3) and passing through the center of gravity of the sample holder (9). Test bench (1) according to claim 11, further comprising a first variable speed motor (10), the first variable speed motor (10) being configured to rotate the sample holder (9) around the rotation axis (X) of the sample holder (9) at a rotation speed chosen for carrying out the test. Test bench (1) according to one of claims 11 or 12, wherein the inlet (12) of the test chamber (3) is located in the upper wall (18) of the test chamber (3), at the intersection between said upper wall (18) and the axis of rotation (X) of the sample holder (9). Test bench (1) according to one of claims 1 to 13, in which the mixing reactor (2) comprises a turbine and a second variable speed motor, the second variable speed motor being configured to drive the turbine in rotation, the mixing of the new erosive particles (7) with the corrosive fluid being carried out under the effect of the rotation of said turbine. Test bench (1) according to one of claims 1 to 14, in which the mixing reactor (2) comprises a heating system (25) configured to heat the corrosive fluid during the mixing of said fluid with the new erosive particles (7), so that the homogeneous particle-fluid mixture (8) at the outlet of the mixing reactor (2) is brought to a temperature chosen for carrying out the test. Test bench (1) according to claim 15, wherein the mixing reactor (2) comprises an inner wall and an outer wall, the inner wall and the outer wall forming a double wall of the mixing reactor (2), and wherein the heating system (25) comprises a heat transfer fluid (26) which circulates between the inner wall and the outer wall, so that the heating of the corrosive fluid in the mixing reactor (2) is carried out by heat transfer between the heat transfer fluid (26) and the corrosive fluid through the inner wall. Test bench (1) according to one of claims 1 to 16, wherein the settling system (4) comprises a first settling tank (28) comprising an inlet forming the inlet (14) of the settling system (4) and a second settling tank (29) comprising an outlet forming the outlet (27) of the settling system (4), the first tank (28) further comprising an outlet (30) fluidically connected to an inlet (31) of the second tank (29), the outlet (30) of the first tank (28) being located in an upper part of said first tank (28), so that only an upper part of the particle-fluid mixture decanted in the first tank (28) flows into the second tank (29), the outlet (27) of the settling system (4) being located in an upper part of the second tank (29), so as to sample only the corrosive fluid separated from the erosive particles used to carry out the test, said particles remaining at the bottom of the first tank (28) and the second tank (29). Test bench (1) according to claim 17, wherein the first settling tank (28) is located above the second settling tank (29).

Images