Dilution apparatus for diluting at least one powder in at least one liquid and associated method

Abstract

The invention relates to a dilution apparatus (1) for diluting at least one powder (P) in at least one liquid (L), the dilution apparatus (1) comprising a tank (10) configured to receive a solution (S), a recirculation circuit (20), at least one filtration screen (3) positioned in the tank (10) so as to define a lower enclosure below the filtration screen (3) and an upper enclosure above the filtration screen (3), the recirculation circuit (20) being configured to collect, via the recirculation inlet (21), a flow of solution in the lower enclosure, and also to inject, via the recirculation outlet (22), the flow of solution into the upper enclosure so as to improve the dilution.

Description

Dilution installation for diluting at least one powder in at least one liquid and associated method

[0001] The present invention relates to the field of diluting a urea powder with water to form a urea-based solution used in particular in a diesel-powered motor vehicle. The invention relates more generally to the field of diluting a powder in a liquid.

[0002] To obtain a urea-based solution used in particular in a diesel-powered motor vehicle, urea powder is diluted with water in a dilution plant. In a known manner, urea powder, also called urea granules CH4N2O, is stored in large-capacity bags, for example, of the order of 1000 kg. In a bag, the urea powder can be agglomerated to form powder blocks.

[0003] In a known manner, with reference to the, a dilution installation 100 according to the prior art comprises a first unit 110, in which the urea powder is treated so as to break the powder blocks, a conveyor 120 and a second unit 130 in which the urea powder is mixed with water.

[0004] In practice, the first unit 110 comprises a support 111 for suspending a bag of powder Sp, a platform 112 to allow an operator to unlace the bag Sp, a lump breaker 113 for breaking up the powder blocks, a lock 114 for regulating the supply of powder to the conveyor 120. The conveyor 120 is preferably depressurized. The first unit 110 operates by gravity and the platform 112 is raised and generally accessible by stairs. The second unit 130 comprises a dilution tank 131 with a powder inlet 132, a fluid inlet 133, an agitator 134 and a fluid outlet 135 associated with a transfer pump 136.

[0005] A 100 dilution system has several disadvantages. First of all, generally speaking, such a 100 dilution system is very bulky and expensive due to the multiplication of equipment. The electrical consumption of each equipment is high and requires high maintenance (cleaning, repair, etc.) related to the handling of the powder. In addition, an operator must unlace the bag in an elevated position, which requires the provision of safety devices that further increase the cost and space requirement.

[0006] The invention was originally developed for the dilution of urea powder in water, but it finds advantageous application for the dilution of different powders in different liquids, for example, powdered sebacic acid mixed with potash lye to obtain antifreeze.

[0007] The invention thus aims to eliminate at least some of these drawbacks. PRESENTATION OF THE INVENTION

[0008] The invention relates to a dilution installation for diluting at least one powder in at least one liquid, the dilution installation comprising:A tank configured to receive a solution comprising a mixture of the powder and the liquid, the tank comprising at least one powder inlet and at least one liquid inlet,A recirculation circuit comprising at least one recirculation inlet and at least one recirculation outlet,At least one filtration grid positioned in the tank vertically between the recirculation inlet and the recirculation outlet so as to define a lower enclosure below the filtration grid and an upper enclosure above the filtration grid,The recirculation circuit being configured, on the one hand, to take, via the recirculation inlet, a flow of solution from the lower enclosure and, on the other hand, to inject, via the recirculation outlet,the flow of solution into the upper enclosure so as to improve dilution.,

[0009] Thanks to the invention, any powder blocks are advantageously broken up by the combined action of the filtration grid and the recirculation circuit which generates turbulence in the upper enclosure. It is advantageously no longer necessary to provide equipment external to the tank to break up the powder blocks, which reduces the size and costs, and improves safety. The technical equipment is inexpensive and highly reliable, which is advantageous.

[0010] According to one aspect, the at least one recirculation outlet comprises a nozzle configured to perform a peripheral injection into the tank. A peripheral injection makes it possible to generate a peripheral current in the tank, which makes it possible to create turbulence to break up the powder blocks but also makes it possible to sweep the filtration grid to avoid any clogging. Preferably, the nozzle is oriented tangentially.

[0011] According to one aspect, the at least one recirculation outlet is located at a vertical distance from the filtration grid of less than 30 cm, preferably less than 25 cm. This allows the filtration grid to be swept optimally.

[0012] In one aspect, the at least one recirculation outlet is in the form of a first recirculation outlet and a second recirculation outlet, preferably diametrically opposed. This allows for the generation of an optimal peripheral flow throughout the tank.

[0013] According to one aspect, the filter grid has a filter mesh of between 0.1 and 1 mm2. Such a filter mesh is particularly suitable for a urea powder.

[0014] According to one aspect, the dilution installation comprises at least one cutting member configured to open a bag of powder. Such a cutting member makes it possible to avoid any manual operation by the operator above the tank. According to one aspect, the cutting member is in the form of a vertical knife.

[0015] In one aspect, the filter grid is positioned on a support that rests on a bottom of the tank. Such a support allows a traditional tank to be used.

[0016] According to one aspect, the support comprising a set of vertical support walls, several vertical support walls comprising a notch in their lower portion so as to allow the circulation of solution on either side of the vertical support wall.

[0017] In one aspect, the filter grid comprises several independent filter elements. This facilitates manufacturing and maintenance.

[0018] The invention relates to a method for diluting at least one powder in at least one liquid by means of a dilution installation as presented previously, the dilution method comprising steps consisting of:Introducing the powder and the liquid into the tank above the filtration grid so as to form a solution in the lower enclosure and the upper enclosure,Generating a recirculation in the tank by taking a flow of solution from the lower enclosure and injecting it into the upper enclosure so as to improve the dilution. PRESENTATION OF FIGURES

[0019] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0020] This is a schematic representation of a dilution installation according to the prior art.

[0021] This is a schematic representation of a dilution installation according to one embodiment of the invention.

[0022] This is a schematic cross-sectional representation of the tank of the.

[0023] This is a schematic representation of a recirculation circuit.

[0024] This is an exploded schematic representation of a filtration grid and support.

[0025] This is a schematic representation of a step in cutting a bag of powder.

[0026] This is a schematic representation of a recirculation stage.

[0027] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary. DETAILED DESCRIPTION OF THE INVENTION

[0028] With reference to the, the invention will be presented for a dilution installation 1 for the dilution of at least one powder P in at least one liquid L. In this example, the dilution of a urea powder with water will be presented to form a urea-based solution S used in particular in a diesel-powered motor vehicle. It goes without saying that the installation relates more generally to the field of the dilution of a powder in a liquid.

[0029] In this example, the liquid L is reverse osmosis water. The powder P is a urea powder packaged in bags of powder Sp (), in particular, 1000 kg. As previously shown, in a bag Sp, the powder P can be agglomerated to form powder blocks.

[0030] With reference to the, the dilution installation 1 comprises a tank 10 configured to receive a solution S comprising a mixture of powder P and liquid L. The tank 10 may have various shapes and capacities. The tank 10 preferably has a cylindrical shape, more preferably, a circular section. The tank 10 preferably has a capacity of between 10,000 L and 13,000 L.

[0031] The tank 10 has a bottom and a vertical peripheral belt. In this example, the tank 10 also has a cover comprising a powder inlet opening 11. In this example, the tank 10 comprises a cutting member 4 positioned at the level of the powder inlet 11 and configured to open a bag of powder Sp. As illustrated in the, the cutting member 4 is in the form of a vertical knife. In this example, the vertical knife comprises a plurality of teeth 40 to allow the opening of the bag of powder Sp by cutting without generating debris. The teeth 40 preferably have a triangular shape. Furthermore, the teeth 40 preferably have different sizes. The operator can thus open a bag Sp by vertically moving the bag Sp by means of a forklift 9 () in order to empty the contents of the bag Sp, i.e. the powder P, into the tank 10. There is thus no need for the operator to be raised. Safety is thus improved.

[0032] The tank 10 comprises at least one liquid inlet 12, preferably a single one, configured to introduce liquid L into the tank 10. In this example, with reference to the, the liquid inlet 12 is positioned in the upper part of the tank 10.

[0033] The tank 10 comprises at least one distribution outlet 13, preferably a single one, configured to distribute the solution S once the dilution has been completed. This makes it possible in particular to fill containers with a solution having the desired dilution rate.

[0034] In this example, with reference to the, the dilution installation 1 comprises at least one filtration grid 3 positioned in the tank 10 so as to define a lower enclosure E1 below the filtration grid 3 and an upper enclosure E2 above the filtration grid 3.

[0035] Preferably, the dilution installation 1 only comprises a single filtration grid 3 so as to have a reduced cost. It goes without saying that the dilution installation 1 could comprise several.

[0036] Preferably, the filtration grid 3 is positioned at a height between 13% and 17% of the height of the tank 10. In this example, the tank 10 has a height of around 180cm and the filtration grid 3 is positioned at a height of 27cm.

[0037] Preferably, the filtration grid 3 has a filtration mesh of between 0.1 and 1 mm2. Such a filtration mesh advantageously makes it possible to prevent blocks of powder from being present in the lower enclosure E1. This makes it possible to ensure that the solution S is homogeneous in the lower enclosure E1.

[0038] The filtration grid 3 can be held in the tank 10 by various mechanical members, for example, by bolting or by pressing on a support as will be shown in the figure. Preferably, the tank 10 comprises at least one access hatch 14, preferably lateral, to allow practical access to the filtration grid 3.

[0039] With reference to the, the filtration grid 3 is preferably modular so as to facilitate its manufacture and maintenance. For example, with reference to the, the filtration grid 3 comprises several independent filtration elements 30 assembled on a frame 31. In this example, the filtration elements 30 are in the form of perforated plates, in particular triangular. The frame 31 has a peripheral contour 311 configured to match the horizontal section of the tank 10 and to delimit in a substantially sealed manner the lower enclosure E1 and the upper enclosure E2. The frame 31 has openings 312 for receiving the filtration elements 30.

[0040] In this example, with reference to the, the filtration grid 3 is positioned on a support 32 which rests in the bottom of the tank 10. The support 32 comprises a set of vertical support walls 320. In this example, several vertical support walls 320 comprise a notch 321 in their lower portion so as to allow the circulation of solution S on either side of the vertical support wall 320. As will be presented later, this allows the solution S to circulate from the upper enclosure E2 to the lower enclosure E1 via the filtration grid 3 and then to reach the liquid outlet 13 formed at the periphery of the tank 10 by passing via the notches 321.

[0041] In this example, with reference to the, the dilution installation 1 comprises a recirculation circuit 20 comprising at least one recirculation inlet 21 and at least one recirculation outlet 22. The circulation circuit 20 is configured to conduct a flow of solution F1 from the recirculation inlet 21 to the recirculation outlet 22. In this example, the recirculation circuit 20 comprises a drive pump 23 to drive the flow of solution F1 but it goes without saying that other means could be suitable.

[0042] As illustrated in , the recirculation inlet 21 has an inlet height H1 and the recirculation outlet 22 has an outlet height H2.

[0043] With reference to the, the filtration grid 3 is positioned in the tank 10 vertically between the recirculation inlet 21 and the recirculation outlet 22. In other words, the filtration grid 3 has a grid height H3 between the inlet height H1 and the outlet height H2.

[0044] The recirculation circuit 20 is configured, on the one hand, to take, via the recirculation inlet 21, a flow of solution F1 from the lower enclosure E1 and, on the other hand, to inject, via the recirculation outlet 22, the flow of solution F1 into the upper enclosure E2 so as to improve the dilution.

[0045] By means of the invention, a flow of solution F1 is injected into the upper enclosure E2 which possibly includes blocks of powder. This advantageously makes it possible to break up the blocks of powder and facilitate their dilution so that all the powder P is diluted homogeneously in the upper enclosure E2 and in the lower enclosure E1.

[0046] In order to break up the powder blocks and accelerate dilution, the flow of solution F1 is injected at high speed, in particular, at a speed between 4m / s and 6m / s. The drive pump 23 advantageously allows the speed to be adjusted.

[0047] In order to promote the appearance of turbulences advantageous to dilution, with reference to the, the recirculation circuit 20 comprises a first recirculation outlet 22 and a second recirculation outlet 22, preferably diametrically opposed. It goes without saying that the circulation circuit 20 could comprise a single or more than two recirculation outlets 22.

[0048] Preferably, each recirculation outlet 22 comprises a nozzle 220 configured to carry out a peripheral injection into the tank 10, that is to say, in a cyclonic manner into the tank 10. Preferably, each nozzle 220 is oriented tangentially in the tank 10. Such an injection makes it possible to increase the turbulence and to promote rapid and homogeneous dilution of the powder P. The mixture is also made homogeneous as will be presented later.

[0049] In this example, with reference to the, the distribution outlet 13 is connected to the recirculation inlet 21 so as to reduce the complexity of the dilution installation 1. In particular, a valve 24 is mounted at the recirculation inlet 21 so as to allow either recirculation to the recirculation outlets 22 or distribution of the product via the distribution outlet 13.

[0050] An example of the implementation of a process for diluting a powder P in a liquid L using a dilution installation 1 will now be presented.

[0051] The dilution method comprises a step of introducing the powder P and the liquid L into the tank 10 above the filtration grid 3. In particular, with reference to the, the tank 10 is filled with a predetermined quantity of liquid L, in particular osmosis water, which is introduced via the liquid inlet 12. Then, the operator moves a bag of powder Sp with a forklift 9 so as to position it above the powder inlet 11 so that it can open and empty into the tank 10 thanks to the cutting member 4. The operator can empty several bags Sp in order to obtain the desired dilution rate.

[0052] When the powder P is deposited in the tank 10, the non-agglomerated powder passes through the filtration grid 3 and is deposited in the lower enclosure E1 while the powder agglomerated into powder blocks remains in the upper enclosure E2.

[0053] The method comprises a step of generating recirculation in the tank by taking a flow of solution F1 from the lower enclosure E1 and injecting it into the upper enclosure E2 so as to improve the dilution. For this purpose, the valve 24 is positioned so as to allow recirculation between the recirculation inlet 21 and the two recirculation outlets 22. The operator activates the drive pump 23 so as to generate recirculation in the tank 10 which makes it possible to increase the mixing between the powder P and the liquid L. A peripheral current is generated in the tank 10. The recirculation makes it possible to generate cyclonic and kinetic turbulence which makes it possible to drive the solution S through the filtration grid 3 to break up the powder blocks. The current also makes it possible to reduce the risk of clogging.Advantageously, the solution S which circulates through the drive pump 23 is filtered, which avoids any risk of premature damage. Preferably, recirculation is maintained as long as the solution is not homogeneous between the lower enclosure E1 and the upper enclosure E2.

[0054] Once a homogeneous solution is obtained, the operator modifies the position of the valve 24 so as to direct the solution S towards the distribution outlet 13 in order to distribute it into containers or into another installation.

[0055] Thanks to the invention, a homogeneous dilution can be achieved with limited technical equipment, low cost, and a long service life. The footprint and cost are significantly reduced. In addition, operator safety is improved since it is no longer necessary to carry out physical operations at height. Dilution is also carried out more quickly with better homogeneity. This advantageously promotes the installation of dilution installations in a territory.

[0056] The invention is very advantageous for diluting urea powder in water but it finds advantageous application for diluting different powders in different liquids, for example, powdered sebacic acid mixed with potash lye to obtain antifreeze.

Claims

Dilution installation (1) for diluting at least one powder (P) in at least one liquid (L), the dilution installation (1) comprising:A tank (10) configured to receive a solution (S) comprising a mixture of the powder (P) and the liquid (L), the tank (10) comprising at least one powder inlet (11) and at least one liquid inlet (12),A recirculation circuit (20) comprising at least one recirculation inlet (21) and at least one recirculation outlet (22),At least one filtration grid (3) positioned in the tank (10) vertically between the recirculation inlet (21) and the recirculation outlet (22) so as to define a lower enclosure (E1) below the filtration grid (3) and an upper enclosure (E2) above the filtration grid (3),The recirculation circuit (20) being configured, on the one hand, to take, via the inlet of recirculation (21), a flow of solution (F1) in the lower enclosure (E1) and, on the other hand,to inject, via the recirculation outlet (22), the flow of solution (F1) into the upper enclosure (E2) so as to improve the dilution, the filtration grid (3) being positioned on a support (32) which rests on a bottom of the tank (10), the support (32) comprising a set of vertical support walls (320), several vertical support walls (320) comprising a notch (321) in their lower portion so as to allow the circulation of solution (S) on either side of the vertical support wall (320), Dilution installation (1) according to claim 1, in which the at least one recirculation outlet (22) comprises a nozzle (220) configured to carry out a peripheral injection into the tank (10). Dilution installation (1) according to one of claims 1 to 2, in which the at least one recirculation outlet (22) is located at a vertical distance from the filtration grid (3) of less than 30 cm. Dilution installation (1) according to one of claims 1 to 3, in which the at least one recirculation outlet (22) is in the form of a first recirculation outlet and a second recirculation outlet, preferably diametrically opposite. Dilution installation (1) according to one of claims 1 to 4, in which the filtration grid (3) has a filtration mesh of between 0.1 and 1 mm2. Dilution installation (1) according to one of claims 1 to 5, comprising at least one cutting member (4) configured to open a bag of powder (Sp). Dilution installation (1) according to one of claims 1 to 6, in which the filtration grid (3) comprises several independent filtration elements (30). Method for diluting at least one powder (P) in at least one liquid (L) by means of a dilution installation (1) according to one of claims 1 to 7, the dilution method (1) comprising steps consisting of:Introducing the powder (P) and the liquid (L) into the tank (10) above the filtration grid (3) so as to form a solution (S) in the lower enclosure (E1) and the upper enclosure (E2),Generating a recirculation in the tank by taking a flow of solution (F1) from the lower enclosure (E1) and injecting it into the upper enclosure (E2) so as to improve the dilution.

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