Vibrator on the lye filter

Abstract

The present invention relates to a lye filtering unit (10) capable of filtering ferrous residues and iron precipitates as well as any other impurity present in an electrolyte solution produced by an electrolysis unit, the lye filtering unit (10) comprising a tank (12) comprising a side wall (14) and at least one wave-generating element (16) placed against the side wall (14).

Description

[0001] DESCRIPTION

[0002] TITLE: Vibrator on the lye filter

[0003] Technical field of the invention

[0004] The present invention relates to a lye filtering unit capable of filtering ferrous residues and iron precipitates as well as any other substance present in an electrolyte solution resulting from an electrolysis unit, for example for the production of dihydrogen (H2) and dioxygen (02).

[0005] The invention relates more particularly to a lye filtering unit designed to facilitate its maintenance and to a method of maintaining such a lye filtering unit.

[0006] Technical background

[0007] The lye filter, also called lye filter unit, is used to filter mainly ferrous residues as well as iron precipitates without forgetting, to a lesser extent, other substances of a different nature. Said lye filter consists of two main parts: i) at least one magnetic bar(s) to recover magnetic particles (regardless of size), and ii) a basket supporting an inner sieve formed of a tight metal mesh dedicated to the capture of non-magnetic particles (regardless of size). Following this particle capture action, said lye filter must be cleaned of these iron agglomerates as well as minority substances on a recurring basis to maintain the efficiency of the system. All iron agglomerates, minority substances and filtered molecules are considered as impurities.

[0008] Currently, this maintenance operation is quite heavy and not very easy, given the mass and steric bulk of said lye filter as well as those linked to the magnetic bar(s) and the basket within the lye filter.

[0009] The elements making the maintenance operation difficult are the following: i) the basket containing a sieve formed of a tight metal mesh, extremely heavy, which is fixed by means of screws on a wedge of the side wall of the lye filter and which is characterized by the fact that the bottom is located near the lower end of said lye filter, and ii) the magnetic bar(s) which is (are) directly fixed on the cover of said lye filter, said cover being surmounted by at least one handle necessary for lifting the assembly composed of the cover and the magnetic bar(s).

[0010] Thus, when handling said lye filter, various significant obstacles linked to points i) and ii) defined above can be listed, including:

[0011] - the detachment of the basket is quite complex given: i) the difficult accessibility of the latter since it is located at a certain depth in relation to the inlet of the lye filter, ii) the significant mass of the basket to be extracted, and iii) human intervention to remove the screws, the intervention being difficult due to the narrowness inside the lye filter;

[0012] - handling the lid using at least one handle when opening the lye filter by human intervention is particularly difficult because the lid alone has a significant mass. During this handling, it is important to also take into consideration the mass and size of the magnetic bar(s) directly attached to said lid to be lifted. In other words, the cumulative mass is very high on the one hand and on the other hand, the handling is very complex due to the significant length of the magnetic bar(s) to be lifted and extracted.

[0013] Thus, there is an interest i) in reducing the frequency of handling of the lye filter and, ultimately, ii) in facilitating the maintenance operation of the latter. Summary of the invention

[0014] The invention relates to a lye filtering unit capable of filtering ferrous residues and iron precipitates as well as any other impurities in an electrolyte solution from an electrolysis unit, the lye filtering unit comprising:

[0015] - a tank comprising a side wall, the lye filtering unit further comprising:

[0016] - at least one wave generating element placed against the side wall. According to other characteristics of the invention: the tank extending along either a main direction of vertical elongation, or a main direction of horizontal elongation, or any main direction of elongation between the horizontal and vertical planes defined according to the reference V, L, T, and comprising a side wall, the wave generating element is placed against the side wall;

[0017] - the tank further comprising a lye inlet orifice and a lye outlet orifice, the wave generating element is placed at any height against the side wall, more particularly at an intermediate height between the height of the inlet orifice and the height of the outlet orifice and preferably halfway between the inlet orifice and the outlet orifice;

[0018] - the lye filtering unit comprises at least one wave generating element and preferably at least two wave generating elements placed symmetrically with respect to the vertical axis or the horizontal axis or to any main elongation direction between the horizontal and vertical planes defined according to the reference V, L, T, of the tank;

[0019] - the wave generating element is an air gun capable of generating a mechanical wave by means of a jet of pressurized air;

[0020] - the lye filter unit has a pressurized air supply pipe common to all wave generating elements;

[0021] - the wave generating element is a vibrator capable of generating a mechanical wave;

[0022] - the wave generating element is capable of generating an electromagnetic wave;

[0023] - the lye filter unit includes a wave generating element control unit.

[0024] The invention also relates to a method for maintaining a lye filtering unit according to the invention, the method comprising a step of generating waves by means of at least one wave generating element. According to the other characteristics of the invention:

[0025] - wave generation is carried out with a regular frequency; - wave generation is carried out with an increasing frequency;

[0026] - wave generation is carried out with a frequency proportional to the flow of lye passing through the lye filtering unit;

[0027] - wave generation is carried out with constant intensity;

[0028] - wave generation is carried out with increasing intensity;

[0029] - wave generation is carried out with an intensity proportional to the flow of lye passing through the lye filter unit.

[0030] Brief description of the figures

[0031] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0032] [Fig.1] is a perspective view of a lye filtering unit according to the invention equipped with a wave generating assembly composed of six wave generating elements;

[0033] [Fig.2] is a perspective view showing the wave generating assembly composed of six wave generating elements shown in Fig. 1;

[0034] [Fig.3] is a schematic sectional view of a lye filter unit according to the invention which shows the fouling of the magnetic bars and the basket before the generation of a wave in the lye filter unit;

[0035] [Fig.4] is a schematic cross-sectional view of the lye filter unit of Figure 3 showing the de-fouling of the magnetic bars and basket following the generation of a wave in the lye filter unit and the deposition of impurities in the bottom of the basket.

[0036] Detailed description of the invention

[0037] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the reference V, L, T indicated in the figures, the longitudinal L and transverse T axes of which extend in a horizontal plane, will be adopted as a non-limiting example and without limiting reference to Earth's gravity. By convention, the vertical axis V is oriented from bottom to top and the longitudinal axis L is oriented from back to front. In the description which follows, identical, similar or analogous elements will be designated by the same reference numbers.

[0038] The invention relates to a lye filtering unit 10 capable of filtering ferrous residues and iron precipitates as well as any other impurity in an electrolyte solution resulting from an electrolysis unit. The innovation is based on placing at least one wave generator at the periphery of the lye filtering unit 10 capable of eliminating clogging and concretions within the lye filtering unit 10.

[0039] In Figure 1, a lye filtering unit 10 according to the invention is shown. The lye filtering unit 10 comprises a tank 12 extending in a main direction of vertical elongation A between a lower surface 28 and an upper surface 30. The lye filtering unit 10 comprises a side wall 14.

[0040] The tank 12 has a generally cylindrical shape with axis A and circular section. The side wall 14 is curved and extends along the circumference of the cylinder formed by the tank. The side wall 14 is parallel to the axis A. Any other geometric configuration defining the side wall 14 falls within the description of the present invention given that the technical characteristics associated with the latter are independent of the geometric configuration.

[0041] To allow access to the interior of the tank 12, the upper face 30 has an opening 32. The lye filtering unit 10 has a cover 34 capable of cooperating with the upper surface 30 of the tank 12 to close the opening 32 and allow the tank 12 to be hermetically closed.

[0042] According to a characteristic of the invention, the lye filtering unit 10 comprises at least one wave generating element 16 placed against the side wall 14. The wave generating element 16 is placed against the external face of the side wall 14, the external face being visible in FIG. 1.

[0043] The wave generating element 16 is fixed to the side wall 14 for example by means of bolting, screwing, a set of stops, welding, gluing or by any other fixing means.

[0044] Alternatively, the wave generating element 16 could be placed against another wall of the lye filter unit 10, for example against the lower surface 28 or against the upper surface 30, on an external face.

[0045] The wave generating element 16 could also be fixed on an inner wall of the lye filter unit 10.

[0046] It should be noted that the term "wall" is used in a broad sense such that the term "wall" includes any surface of the lye filter unit 10 including the cover 34.

[0047] The tank 12 has a lye inlet orifice 18 and a lye outlet orifice 20. The wave generating element 16 is placed at an intermediate height between the height of the lye inlet orifice 18 and the height of the lye outlet orifice 20 and preferably halfway between the lye inlet orifice 18 and the lye outlet orifice 20.

[0048] In the example shown in Figure 2, the lye filter unit 10 comprises a wave generation assembly 36 16 composed of six wave generation elements 16 placed symmetrically with respect to the axis A of the tank 12. The tank 12 having a generally cylindrical shape with axis A and circular section, the six wave generation elements 16 are arranged along a circle C with axis A and radius R substantially equal to the outer radius of the tank 12 apart from the mounting clearance. The angular difference a between the positions of the six wave generation elements 16 along the circle C is TT / 3. Any other geometric configuration defining the side wall 14 is included in the description of the present invention given that the technical characteristics associated with the latter are independent of the geometric configuration, in other words the wave generation assembly 36 16 will have the same technical purposes, regardless of the location of the latter 36.

[0049] According to one embodiment of the invention, the wave generating element 16 is an air gun capable of generating a mechanical wave by means of a jet of pressurized air. Thus, the air gun generates a deflagration upon contact with the side wall 14 thereby producing mechanical waves which propagate from the side wall 14 into all of the elements of the lye filter unit 10.

[0050] An air cannon, also called a pneumatic declotting device, is composed of two main components: a compressed air tank and a trigger mechanism allowing the high-speed release of compressed air. The trigger mechanism typically includes a solenoid valve with an air tank closing position and an air tank venting position.

[0051] The air cannon is pneumatically connected to a compressed air network 26, for example at a pressure of around 4 bars, or even at a pressure of 5 to 6 bars.

[0052] When the air gun fires, the solenoid valve located on the air circuit instantly purges the air network, creating a sudden vacuum. The piston is then suddenly pushed back by the vacuum, creating an explosion of air suddenly released from the pressure tank. This phase is measured in milliseconds only. The compressed air contained in the pressure tank is instantly released, and the resulting blast evacuates the material sticking to the elements of the lye filter unit 10 thanks to the shock wave obtained.

[0053] The lye filter unit 10 comprises a pressurized air supply pipe 22 common to all the wave generating elements 16. The supply pipe 22 is pneumatically connected to the compressed air network 26. In the example of FIGS. 1 and 2, the supply pipe 22 comprises a portion describing a circle peripheral to the wave generating elements 16 and pneumatically connected to each wave generating element 16 at a pneumatic connection placed on a peripheral part of the wave generating element 16.

[0054] Alternatively, the wave generating element 16 is a vibrator capable of generating a mechanical wave.

[0055] According to another variant, the wave generating element 16 is capable of generating an electromagnetic wave.

[0056] The lye filter unit 10 comprises a control unit 24 for controlling the wave generating elements 16. The control unit 24 may comprise a wired electrical connection with the wave generating assembly 16 or a wireless connection for remote control. The control unit 24 may control the wave generating elements 16 in a synchronized manner or independently. The control unit 24 makes it possible in particular to control the generation of a wave within the lye filter unit 10.

[0057] The invention also relates to a method for maintaining a lye filter unit 10 comprising a step of generating waves by means of the wave generating element 16.

[0058] Figure 3 shows the interior of a lye filter unit 10 before a wave is generated within the lye filter unit 10. Figure 4 shows the interior of the lye filter unit 10 of Figure 3 after a wave is generated within the lye filter unit 10 by the wave generating elements 16.

[0059] The lye filtering unit 10 shown in Figures 3 and 4 comprises a tank 12, a cover 34 capable of cooperating with the upper surface 30 of the tank 12 to close the opening 32.

[0060] The lye filtering unit 10 also comprises at least one magnetic bar 38. In the example shown in Figures 3 and 4, the lye filtering unit 10 has two magnetic bars 38 fixed to the cover 34 and extending vertically downwards from a lower face of the cover 34. The magnetic bars 38 make it possible to retain by magnetization magnetic particles 42 contained in the lye.

[0061] The lye filtering unit 10 further comprises a basket 40 delimiting a cavity 44 extending in the vertical direction A, the basket 40 comprising an upper face 46 comprising a central orifice 48 capable of receiving the magnetic bars 38 and a peripheral rim 50 capable of resting on a wedge 52 placed on an internal face 54 of the tank 12 below the level of the lye inlet orifice 18 and above the level of the lye outlet orifice 20. The basket 40 supports a sieve formed of a tight metal mesh making it possible to retain non-magnetic molecules 56 of a particle size greater than the mesh size of the sieve and which have not been magnetized by the magnetic bars 38.

[0062] Figure 3 shows that the magnetic bars 38 are covered with magnetic particles 42 and that the sieve is clogged with non-magnetic molecules 56. Figure 4 shows that, under the effect of the propagation of the wave in the lye filtering unit 10, the magnetic particles 42 and the non-magnetic molecules 56 have been detached from the magnetic bars 38 and the sieve respectively and have fallen into the bottom of the basket 40.

[0063] The frequency of wave generation is either temporally discontinuous or continuous. Temporally continuous wave generation means wave generation with a regular frequency.

[0064] At the beginning of the operation of the lye filtering unit 10, it is not necessary to continuously generate and apply the waves within the lye filtering unit 10 since the accumulation of agglomerates is very low. On the other hand, over time, the latter tend to develop more, which is why it appears appropriate to increase the frequency of said waves to prevent the impurities from growing significantly and, ultimately, from agglomerating both on the magnetic bars 38 and on the tight metal mesh of the sieve located in the basket 40 in order to drastically slow down the proper operation of the lye filtering unit 10. In other words, these waves are created progressively over time and are characterized by a variable frequency depending on the clogging of the agglomerates.

[0065] Thus, the generation of waves can be carried out with an increasing frequency. Indeed, over time, the basket 40 and the magnetic bars 38 are increasingly fouled by the magnetic particles 42 and by the non-magnetic molecules 56. Thus, when the lye filter unit 10 is started, the basket 40 and the magnetic bars 38 are only slightly fouled and a low wave generation frequency is sufficient. As the lye filter unit 10 operates, the basket 40 and the magnetic bars 38 become increasingly fouled and the wave generation frequency is increased.

[0066] According to a particular embodiment, the generation of waves is carried out with a frequency proportional to the flow of lye passing through the lye filtering unit 10. Thus, when the flow of lye is minimal, the fouling of the basket 40 and the magnetic bars 38 is slower and a low wave generation frequency is sufficient. When the flow of lye is high, the fouling of the basket 40 and the magnetic bars 38 is faster and the wave generation frequency is higher. With regard to the intensity of the waves produced, like the generation and frequency of use of the latter, the conclusion turns out to be similar. Indeed, depending on the quantity of impurities present in the lye filtering unit 10, the waves sent inside the lye filtering unit 10 have an intensity proportional to said quantity of impurities.In other words, the greater and more regular the quantity of lye entering the lye filter unit 10, the more likely it is that the impurities will agglomerate, which is why the intensity of the waves applied must be adapted to make the system continually efficient with regard to the passage of lye.

[0067] According to a main embodiment, the generation of waves is carried out with a constant intensity.

[0068] According to an improvement, the generation of waves is carried out with increasing intensity to respond to the increasing fouling of the lye filter unit 10 described above.

[0069] According to a particular embodiment, the generation of waves is carried out with an intensity proportional to the flow of lye passing through the lye filtering unit 10. Both for the aspects linked to the frequency of these waves and for those dedicated to the intensity of the latter, the approach followed causes in no case and at any time the slightest structural damage to the side wall 14 of the lye filtering unit 10 or to the internal components (magnetic bars 38, basket 40, ...) of the lye filtering unit 10.

[0070] The invention makes it possible to eliminate all of the substances intercepted by the lye filtering unit 10 by making them fall into the bottom of the lye filtering unit 10, namely at the height of the bottom of the basket 40, in other words, the invention makes it possible to slow down the clogging of the lye filtering unit 10, while taking into account the configuration of the lye filtering unit 10.

[0071] Thanks to the present invention, the detachment of the agglomerates on the magnetic bars 38 as well as on the tight metal mesh of the sieve located in the basket 40 will be easier, which will allow the lye filtering unit 10 to operate under optimal conditions without the steric hindrance gradually created within the lye filtering unit 10 by said agglomerates. Under such conditions, after the detachment of said agglomerates, the latter are concentrated and collected at the bottom of the tight metal mesh of the sieve located in the basket 40. Following the progressive accumulation in the bottom of the basket 40 caused by the use of waves, it is easier to clean all the constituents of the lye filtering unit 10 during maintenance since these are partially or even totally devoid of any agglomerate.

[0072] This embodiment of the invention is said to be preferred but it is entirely possible to arrange the different wave generators 16 at any height on the side wall 14 of the lye filter unit 10, in other words either all at the same height, or each of them at different heights. In addition, said wave generators 16 do not specifically have to be placed two by two symmetrically with respect to a main direction of vertical elongation A, in other words they can be placed either symmetrically by having numerical parity or by being present mainly on one side, or in a completely random manner by following the two numerical approaches defined above.

[0073] In a preferred embodiment of the invention, the generation of waves 16 is obtained by considering “air guns” or vibrators. In a non-limiting manner, said waves can be produced from other sources, which implies that the present invention makes it possible to obtain the same results both with all mechanical waves and with all categories of electromagnetic waves.

[0074] The preferred modes described above nevertheless allow any orientation of the lye filtering unit 10 to be considered. Thus, the latter can be arranged in a horizontal main elongation direction B or in any main elongation direction between the horizontal and vertical planes defined according to the reference V, L, T. Regardless of the orientation followed, all the technical characteristics associated with the geometric configurations of the lye filtering unit 10 and constituent elements of the invention (wave generation element 16, magnetic bars 38, basket 40, etc.) described in the description remain identical, giving a set of identical results.

Claims

CLAIMS 1. Lye filtering unit (10) capable of filtering ferrous residues and iron precipitates as well as any other impurity in an electrolyte solution resulting from an electrolysis unit, the lye filtering unit (10) comprising: - a tank (12) comprising a side wall (14) and an opening (32), - a cover (34) capable of closing the opening (32) of the tank (12), - at least one magnetic bar (38) fixed to the cover (34) to allow magnetic particles (42) contained in the lye to be retained by magnetization, - a basket (40) delimiting a cavity (44) comprising a central orifice (48) capable of receiving at least one magnetic bar (38), the lye filtering unit (10) being characterized in that it further comprises: - at least one wave generating element (16) placed against the external face of the side wall (14).

2. Lye filtering unit (10) according to the preceding claim, characterized in that, the tank (12) extending in either a main direction of vertical elongation (A), or a main direction of horizontal elongation (B), or any main direction of elongation between the horizontal and vertical planes defined according to the reference V, L, T, and comprising a side wall (14), the wave generating element (16) is placed against the side wall (14).

3. Lye filter unit (10) according to any one of the preceding claims, characterized in that, the tank (12) further comprising a lye inlet orifice (18) and a lye outlet orifice (20), the wave generating element (16) is placed at any height against the side wall (14), more particularly at an intermediate height between the height of the lye inlet orifice (18) and the height of the lye outlet orifice (20) and preferably halfway between the lye inlet orifice (18) and the lye outlet orifice (20).

4. Lye filter unit (10) according to any one of the preceding claims when dependent on claim 2, characterized in that that the lye filtering unit (10) comprises at least one wave generating element (16) and preferably at least two wave generating elements (16) placed symmetrically with respect to the vertical axis (A) or the horizontal axis (B) or to any main elongation direction between the horizontal and vertical planes defined according to the reference V, L, T, of the tank (12).

5. Lye filter unit (10) according to any one of the preceding claims, characterized in that the wave generating element (16) is an air gun capable of generating a mechanical wave by means of a jet of pressurized air.

6. Lye filtering unit (10) according to the preceding claim, characterized in that it comprises a pressurized air supply pipe (22) common to all the wave generating elements (16).

7. Lye filtering unit (10) according to any one of the preceding claims, characterized in that the wave generating element (16) is a vibrator capable of generating a mechanical wave.

8. Lye filter unit (10) according to any one of the preceding claims, characterized in that the wave generating element (16) is capable of generating an electromagnetic wave.

9. Lye filtering unit (10) according to any one of the preceding claims, characterized in that it comprises a control unit (24) of the wave generating element (16).

10. Method for maintaining a lye filtering unit (10) according to any one of the preceding claims, characterized in that it comprises a step of generating waves by means of the wave generating element (16).

11. Method for maintaining a lye filter unit (10) according to claim 10, characterized in that the generation of waves is carried out with increasing frequency.

12. Method for maintaining a lye filtering unit (10) according to claims 10 or 11, characterized in that the generation of waves is carried out with a frequency proportional to the flow of lye passing through the lye filtering unit (10).

13. Method for maintaining a lye filter unit (10) according to any one of claims 10 to 12, characterized in that the generation of waves is carried out with increasing intensity.

14. Method for maintaining a lye filtering unit (10) according to any one of claims 10 to 13, characterized in that the generation of waves is carried out with an intensity proportional to the flow of lye passing through the lye filtering unit (10).

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