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

Abstract

A 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), a recirculation circuit (20), at least one filter screen (3) positioned in the tank (10) so as to define a lower chamber below the filter screen (3) and an upper chamber above the filter screen (3), the recirculation circuit (20) being configured to, on the one hand, draw, via the recirculation inlet (21), a flow of solution into the lower chamber and, on the other hand, inject, via the recirculation outlet (22), the flow of solution into the upper chamber so as to improve the dilution. Abstract figure: Figure 2

Description

Title of the invention: Dilution installation for diluting at least one powder in at least one liquid and associated method. Technical field

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

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

[0003] In a known manner, with reference to [Fig.1], a prior art dilution installation 100 comprises a first unit 110, in which the urea powder is treated so as to break up 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 suspension support 111 for a bag of powder Sp, a platform 112 to allow an operator to unlace the bag Sp, a lump breaker 113 to break up clumps of powder, and an airlock 114 to regulate 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 elevated 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 drawbacks. First, generally speaking, such a 100 dilution system is bulky and expensive due to the number of pieces of equipment. Each piece of equipment has high power consumption and requires significant maintenance (cleaning, repairs, etc.) related to the handling of the powder. Furthermore, an operator must untie the bag in an elevated position, which necessitates the installation of safety devices that further increase the cost and size.

[0006] The invention originated for the dilution of urea powder in water, but it finds advantageous application for the dilution of various powders in various liquids, for example, sebacic acid powder mixed with potassium 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 powder and 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 filter grid positioned vertically in the tank between the recirculation inlet and the recirculation outlet so as to define a lower enclosure below the filter grid and an upper enclosure above the filter grid, • The recirculation circuit is configured, on the one hand, to draw, via the recirculation inlet, a flow of solution into the lower chamber and, on the other hand, to inject, via the recirculation outlet, the flow of solution into the upper chamber in order to improve dilution.

[0009] Thanks to the invention, any powder clumps are advantageously broken up by the combined action of the filter screen and the recirculation circuit, which generates turbulence in the upper chamber. Advantageously, it is no longer necessary to provide equipment external to the tank to break up the powder clumps, thus reducing space and costs, and improving safety. The technical equipment is inexpensive and highly reliable, which is advantageous.

[0010] According to one aspect, at least one recirculation outlet includes a nozzle configured to perform peripheral injection into the tank. Peripheral injection generates a peripheral current within the tank, creating turbulence to break up powder clumps and also sweeping the filter screen to prevent clogging. Preferably, the nozzle is oriented tangentially.

[0011] According to one aspect, at least the recirculation outlet is located at a vertical distance from the filter grid of less than 30 cm, preferably less than 25 cm. This allows for optimal sweeping of the filter grid.

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

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

[0014] In one aspect, the dilution system includes at least one cutting element configured to open a bag of powder. Such a cutting element eliminates the need for any manual operation by the operator above the tank. In one aspect, the cutting element is in the form of a vertical knife.

[0015] According to one aspect, the filter grid is positioned on a support which rests on the bottom of the tank. Such a support allows the use of a traditional tank.

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

[0017] According to 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 using a dilution apparatus as described above, the dilution method comprising steps consisting of: • Introduce the powder and liquid into the tank above the filter grid so as to form a solution in the lower and upper chambers, • Generate recirculation in the tank by taking a flow of solution from the lower chamber and injecting it into the upper chamber in order to improve dilution. PRESENTATION OF THE 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] Fig. 1 is a schematic representation of a prior art dilution installation.

[0021] Fig. 2 is a schematic representation of a dilution installation according to one embodiment of the invention.

[0022] The [Fig.3] is a schematic cross-sectional representation of the tank of the [Fig.3].

[0023] Fig. 4 is a schematic representation of a recirculation circuit.

[0024] Fig. 5 is a schematic exploded view representation of a filter grid and a support.

[0025] Fig. 6 is a schematic representation of a cutting step of a bag of powder.

[0026] Fig. 7 is a schematic representation of a recirculation step.

[0027] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0028] With reference to [Fig. 2], the invention will be presented for a dilution system 1 for diluting at least one powder P in at least one liquid L. In this example, the dilution of a urea powder with water to form a urea-based solution S, used particularly in a diesel-powered motor vehicle, will be shown. It is understood that the system more generally relates to the field of diluting a powder in a liquid.

[0029] In this example, the liquid L is reverse osmosis water. The powder P is urea powder packaged in powder bags Sp ([Fig. 6]), in particular, 1000 kg bags. As previously shown, in a bag Sp, the powder P can be agglomerated to form powder blocks.

[0030] With reference to [Fig. 2], 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, or more preferably, a circular cross-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 ring. In this example, the tank 10 further has a cover having a powder inlet opening 11. In this example, the tank 10 has a cutting element 4 positioned at the powder inlet 11 and configured to open a bag of powder Sp. As illustrated in [Fig. 2], the cutting element 4 is in the form of a vertical knife. In this example, the vertical knife has a plurality of teeth 40 to allow the bag of powder Sp to be opened 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 using a forklift 9 ([Fig.6]) in order to empty the contents of the bag Sp, i.e. the powder P, into the tank 10. There is therefore no need to raise the operator.Security is thus improved.

[0032] The tank 10 includes 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 [Fig.2], the liquid inlet 12 is positioned in the upper part of the tank 10.

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

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

[0035] Preferably, the dilution installation 1 comprises only a single filter screen 3 in order to have a reduced cost. It is understood that the dilution installation 1 could comprise several.

[0036] Preferably, the filter 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 approximately 180cm and the filter grid 3 is positioned at a height of 27cm.

[0037] Preferably, the filter grid 3 has a filtration mesh size of between 0.1 and 1 mm². Such a filtration mesh advantageously prevents clumps of powder from being present in the lower chamber EL. This ensures that the solution S is homogeneous in the lower chamber EL.

[0038] The filter screen 3 can be held in the tank 10 by various mechanical means, for example, by bolting or by bearing on a support as will be shown in [Fig. 5]. Preferably, the tank 10 has at least one access hatch 14, preferably lateral, to allow convenient access to the filter screen 3.

[0039] With reference to [Fig. 5], the filter grid 3 is preferably modular to facilitate its manufacture and maintenance. By way of example, with reference to [Fig. 5], the filter grid 3 comprises several independent filter elements 30 assembled on a frame 31. In this example, the filter elements 30 are in the form of perforated plates, in particular, triangular ones. The frame 31 has a peripheral contour 311 configured to conform to the horizontal cross-section of the tank 10 and to allow for a substantially watertight separation between the lower chamber E1 and the upper chamber E2. The frame 31 has openings 312 for receiving the filter elements 30.

[0040] In this example, with reference to [Fig. 5], the filter 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 have a notch 321 in their lower portion to allow the flow of solution S on either side of the vertical support wall 320. As will be shown later, this allows the solution S to flow from the upper chamber E2 to the lower chamber E1 via the filter grid 3 and then to the liquid outlet 13 formed at the periphery of the tank 10 by passing through the notches 321.

[0041] In this example, with reference to [Fig.2], the dilution installation 1 includes 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 Fl from the recirculation inlet 21 to the recirculation outlet 22. In this example, the recirculation circuit 20 includes a drive pump 23 to drive the flow of solution Fl, but it is understood that other means could be suitable.

[0042] As illustrated in [Fig.3], the recirculation inlet 21 has an inlet height H1 and the recirculation outlet 22 has an outlet height H2.

[0043] With reference to [Fig.3], the filter grid 3 is positioned vertically in the tank 10 between the recirculation inlet 21 and the recirculation outlet 22. In other words, the filter 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 draw, via the recirculation inlet 21, a flow of solution Fl into the lower chamber El and, on the other hand, to inject, via the recirculation outlet 22, the flow of solution Fl into the upper chamber E2 so as to improve the dilution.

[0045] Thanks to the invention, a flow of solution Fl is injected into the upper chamber E2, which may contain blocks of powder. This advantageously breaks up the powder blocks and facilitates their dilution so that all the powder P is homogeneously diluted in the upper chamber E2 and in the lower chamber EL

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

[0047] In order to promote the appearance of turbulence advantageous to dilution, with reference to [Fig.4], 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 include a single or more than two recirculation outlets 22.

[0048] Preferably, each recirculation outlet 22 has a nozzle 220 configured to perform a peripheral injection into the tank 10, i.e., cyclonically into the tank 10. Preferably, each nozzle 220 is oriented tangentially into the tank 10. Such an injection increases turbulence and promotes rapid and homogeneous dilution of the powder P. The mixture is also made homogeneous as will be shown later.

[0049] In this example, with reference to [Fig.2], 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 process includes a step of introducing the powder P and the liquid L into the tank 10 above the filter screen 3. In particular, with reference to [Fig. 7], the tank 10 is filled with a predetermined quantity of liquid L, in particular reverse 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 by means of the cutting member 4. The operator can empty several bags Sp in order to obtain the desired dilution ratio.

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

[0053] The process includes a step of generating recirculation in the tank by drawing a flow of solution Fl from the lower chamber E1 and injecting it into the upper chamber E2 to improve dilution. For this purpose, valve 24 is positioned to allow recirculation between the recirculation inlet 21 and the two recirculation outlets 22. The operator activates the drive pump 23 to generate recirculation in tank 10, which increases the mixing of the powder P and the liquid L. A peripheral current is generated in tank 10. The recirculation generates cyclonic and kinetic turbulence that drives the solution S through the filter screen 3 to break up powder clumps. The current also reduces the risk of clogging.Advantageously, the solution S circulating through the drive pump 23 is filtered, thus preventing any risk of premature damage. In a way... Preferably, recirculation is maintained until the solution is homogeneous between the lower enclosure El and the upper enclosure E2.

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

[0055] Thanks to the invention, homogeneous dilution can be achieved with limited, low-cost, and long-lasting technical equipment. The size and cost are significantly reduced. Furthermore, operator safety is improved since physical work at height is no longer required. Dilution is also carried out more quickly and with greater homogeneity. This advantageously facilitates the installation of dilution systems across a given area.

[0056] The invention is very advantageous for the dilution of urea powder in water, but it also finds an advantageous application for the dilution of different powders in different liquids, for example, sebacic acid powder mixed with potassium lye to obtain antifreeze.

Claims

Demands

1. 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 filter screen (3) positioned vertically in the tank (10) between the recirculation inlet (21) and the recirculation outlet (22) so as to define a lower enclosure (E1) below the filter screen (3) and an upper enclosure (E2) above the filter screen (3), • The recirculation circuit (20) being configured, on the one hand, to draw, via the recirculation inlet (21),a flow of solution (Fl) in the lower chamber (E1) and, on the other hand, to inject, via the recirculation outlet (22), the flow of solution (Fl) into the upper chamber (E2) so as to improve the dilution, the filter 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) having a notch (321) in their lower portion so as to allow the circulation of solution (S) on both sides of the vertical support wall (320),

2. Dilution installation (1) according to claim 1, wherein at least one recirculation outlet (22) has a nozzle (220) configured to perform peripheral injection into the tank (10).

3. Dilution installation (1) according to any one of claims 1 to 2, wherein at least one recirculation outlet (22) is located at a vertical distance from the filter grid (3) of less than 30 cm.

4. Dilution installation (1) according to any one of claims 1 to 3, wherein at least one recirculation outlet (22) is in the form of a first recirculation outlet and a second recirculation outlet, preferably diametrically opposed.

5. Dilution installation (1) according to any one of claims 1 to 4, wherein the filter grid (3) has a filtration mesh size between 0.1 and 1 mm2.

6. Dilution installation (1) according to any one of claims 1 to 5, comprising at least one cutting member (4) configured to open a bag of powder (Sp).

7. Dilution installation (1) according to any one of claims 1 to 6, wherein the filter grid (3) comprises several independent filter elements (30).

8. A method for diluting at least one powder (P) in at least one liquid (L) using a dilution apparatus (1) according to any one of claims 1 to 7, the dilution method (1) comprising steps consisting of: Introduce the powder (P) and the liquid (L) into the tank (10) above the filter grid (3) so as to form a solution (S) in the lower chamber (E1) and the upper chamber (E2), Generate recirculation in the tank by taking a flow of solution (Fl) from the lower chamber (El) and injecting it into the upper chamber (E2) in order to improve dilution.

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