Device for treating at least one liquid comprising at least one negative pressure column and one foam collector equipped with a gravity drainage system operating by negative pressure

Abstract

The invention relates to a device for treating at least one liquid, comprising: at least one negative pressure column (54); - at least one vacuum generator (52) configured to generate, during operation, a first liquid height (H54) in the negative pressure column (54); - at least one foam collector (64); - at least one drainage system (72) for the foam collector (64), comprising: o at least one continuous drainage duct (76) connected to a drainage port (64.2) of the foam collector (64); o at least one system (80) for keeping a permanent liquid column at a second liquid height (H76) in the continuous drainage duct (76); o the second liquid height (H76) being between the first liquid height (H54) and the first liquid height (H54) + 30% of the first liquid height.

Description

[0001] A device for treating at least one liquid, comprising at least one vacuum column and a foam collector equipped with a gravity-fed drainage system operating by vacuum.

[0002] This application relates to a liquid treatment device comprising a vacuum column and a foam collector equipped with a gravity-fed drainage system operating by vacuum.

[0003] According to an embodiment visible in Figure 1 and described in documents FR2914296, FR2952370 and US2022 / 0024782, a water treatment device 10 for a basin 12 comprises a set of riser and downramps 14, a supply conduit for the water to be treated 16 connecting the basin 12 and the set of riser and downramps 14, and a treated water return conduit 18 connecting the set of riser and downramps 14 and the basin 12. The basin 12 has a liquid height H12.

[0004] The riser and downr assembly 14, also called a vacuum column, comprises an enclosure 14.1, vertical partitions 14.2 positioned in the enclosure 14.1 and delimiting at least one riser 14.3 and at least one downr 14.4 as well as at least one pressurized gas injection system 14.5 which opens into the riser 14.3.

[0005] The enclosure 14.1 contains a first liquid phase PLI which has a first liquid surface SL1 and a first gaseous space 20 located above the first liquid surface SL1. The latter has a liquid height H14.

[0006] The treatment device 10 also includes a vacuum pump 22, connected to the first gaseous sky 20, allowing a depression to be obtained at the level of the first gaseous sky 20 and to form a depression in the riser column 14.3.

[0007] During operation, foam forms at the level of the first gaseous sky 20.

[0008] The treatment device 10 includes a foam collector 24 which comprises a sealed enclosure 24.1 containing a second liquid phase PL2 and a second gaseous space 26 located above the second liquid phase PL2. The foam collector 24 includes a drain port 24.2 opening into the lower part of the enclosure 24.1.

[0009] In addition, the treatment device 10 includes at least a first conduit 28 connecting the first gaseous sky 20 of the riser and downrr assembly 14 and the second gaseous sky 26 of the foam collector 24 and at least a second conduit 30 connecting the second gaseous sky 26 of the foam collector 24 and the vacuum pump 22.

[0010] After a certain period of operation, the foam collector 24 must be emptied.

[0011] According to one embodiment, the treatment device 20 includes a drainage system 32 which comprises a drainage conduit 32.1 connected to the drainage port 24.2 of the foam collector 24, a drainage valve 32.2, at least one level sensor 32.3 positioned in the enclosure 24.1 of the foam collector 24, a drainage pump 32.4 for emptying the enclosure 24.1 of the foam collector 24 and an automation system for managing the operation of the drainage valve 32.2 and the drainage pump 32.4.

[0012] This embodiment is not satisfactory because the treatment must be interrupted when emptying the foam collector 24, by stopping the operation of the vacuum pump 22.

[0013] According to another issue, the presence of a level sensor 32.3, a drain valve 32.2 and a drain pump 32.4 leads to an increase in the cost of the treatment device 10 and the risks of failure.

[0014] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0015] To this end, the invention relates to a device for treating at least one liquid to be treated, comprising: at least one reservoir configured to contain, in operation, said at least one liquid to be treated, which has a liquid surface within the reservoir; at least one set of rising and falling columns, which includes: o a first sealed enclosure configured to contain, in operation, a first liquid phase with a first liquid surface and a first gaseous space located above the first liquid surface; o at least one vertical partition, positioned in the first enclosure, which delimits at least one rising column connected to the reservoir and at least one falling column connected to the reservoir; o at least one gas injection system configured to inject at least one gas into the rising column.at least one foam collector comprising a second sealed enclosure configured to contain, in operation, a second liquid phase with a second liquid surface and a second gaseous space located above the second liquid surface, the second enclosure comprising at least one drain port, at least one vacuum generator configured to generate, in operation, a first liquid height in the first enclosure of the riser and downrix assembly equal to a distance measured in a vertical direction between the reservoir liquid surface and the first liquid surface, at least one first conduit opening into the first and second enclosures and configured to connect the first and second gaseous spaces, at least one second conduit connected to the vacuum generator and opening into the second enclosure, configured to connect the second gaseous space and the vacuum generator,at least one drainage system comprising at least one continuous drainage conduit between a first end connected to the drainage port of the foam collector and a second end.

[0016] According to the invention, the drainage system includes at least one system for maintaining a permanent liquid column of a second liquid height in the continuous drainage conduit, the second liquid height being between the first liquid height and the first liquid height + 30% of the first liquid height.

[0017] This solution allows for automatic control of the level of the second liquid surface in the foam collector without moving components such as valves or pumps. It also reduces the costs of the treatment system and its maintenance.

[0018] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:

[0019] Figure 1 is a schematic representation of a processing device illustrating one embodiment of the prior art, and

[0020] Figure 2 is a schematic representation of a processing device illustrating a first embodiment of the invention, and Figure 3 is a schematic representation of a processing device illustrating a second embodiment of the invention.

[0021] According to embodiments visible in Figures 2 and 3, a treatment device 50 for at least one liquid to be treated comprises: at least one reservoir 52 configured to contain in operation said at least one liquid to be treated, at least one set of rising and falling columns 54 also called a vacuum column, at least one supply conduit 56 for the liquid to be treated connecting the reservoir 52 and the set of rising and falling columns 54, at least one return conduit 58 for the treated liquid connecting the set of rising and falling columns 54 and the reservoir 52.

[0022] In one application, the treated liquid is an effluent. Of course, the invention is not limited to this application.

[0023] During operation, the liquid to be treated contained in the tank 52 has a liquid surface area SL52. The liquid to be treated contained in the tank 52 has a liquid height H52 (or a first hydrostatic pressure) corresponding to the distance separating the bottom of the tank 52 and the liquid surface area SL52.

[0024] The set of rising and falling columns 54 includes a first sealed enclosure 54.1 and at least one vertical partition 54.2, positioned in the first enclosure 54.1, delimiting at least one rising column 54.3 and at least one falling column 54.4.

[0025] According to one configuration, the riser and downr assembly 54 includes at least one gas injection system 54.5 configured to inject at least one gas into the riser 54.3.

[0026] In one arrangement, the riser 54.3 is cylindrical and the downpipe 54.4 is positioned around the riser 54.3 and is in the form of an annular conduit. Additionally, the gas injection system 54.5 is configured to inject pressurized gas at the base of the riser 54.3.

[0027] Of course, the invention is not limited to this arrangement for the gas injection system 54.5 and the riser and downr columns 54.3, 54.4. To give an order of magnitude, the assembly of riser and downr columns 54 has a height greater than 1 m, generally several meters.

[0028] The first chamber 54.1 of the riser and downr column assembly 54 is configured to contain, during operation, a first liquid phase PLI which has a first liquid surface SL1 and a first gaseous head 60 located above the first liquid surface SL1. The first liquid phase PLI has a first liquid height H54 (or a vacuum pressure) equal to a distance measured in the vertical direction between the reservoir liquid surface SL52 of the reservoir 52 and the first liquid surface SL1 in the first chamber 54.1 of the riser and downr column assembly 54.

[0029] The treatment device 50 also includes at least one vacuum pump 62, connected to the first gaseous head 60, enabling a vacuum to be created at the level of the first gaseous head 60 and to form a vacuum in the riser 54.3. This vacuum pump 62 is configured to generate, during operation, a desired first liquid height H54 in the riser and descender assembly 54. Depending on one configuration, the first liquid height H54 is approximately 5 m. The liquid height H52 of the reservoir 52 is approximately 1 m.

[0030] Of course, the invention is not limited to this embodiment. The vacuum pump 62 can be replaced by any vacuum generator configured to generate, during operation, a first liquid height H54 in the rising and falling column assembly 54.

[0031] The treatment device 50 includes at least one foam collector 64 comprising a second sealed chamber 64.1 in which a second liquid phase PL2 is formed, which has a second liquid surface SL2, during operation. The second chamber 64.1 also contains a second gaseous space 66 located above the second liquid surface SL2.

[0032] The foam collector 64 includes at least one drain orifice 64.2 positioned at a low point of the second enclosure 64.1.

[0033] In addition, the treatment device 50 includes at least one first conduit 68 opening into the first and second chambers 54.1, 64.1 and configured to connect the first gaseous space 60 of the riser and downramp assembly 54 and the second gaseous space 66 of the foam collector 64, as well as at least one second conduit 70 connecting the second gaseous space 66 of the foam collector 64 and the vacuum pump 62. The first conduit 68 has a first end 68.1 opening into the first chamber 54.1 of the riser and downramp assembly 54 above the first liquid surface SL1, in the first gaseous space 60, and a second end 68.2 opening into the second chamber 64.1 of the foam collector 64 above the second liquid surface SL2, in the second gaseous space 66. The second conduit 70 has a first end 70.1 which leads into the second enclosure 64.1 of the foam collector 64, above the second liquid surface SL2 in the second gaseous sky 66, as well as a second end 70.2 connected to the vacuum pump 62.

[0034] The reservoir 52, the riser and downr assemblies 54, the foam collector 64 and the vacuum pump 62 are not described in more detail as they may be identical to those of the prior art.

[0035] The treatment device 50 includes at least one drainage system 72 configured to empty at least partially the foam collector 64 and evacuate the second liquid phase PL2 present in the second enclosure 64.1 as soon as the second liquid surface SL2 reaches a trigger height.

[0036] According to a first embodiment visible in Figure 2, the drainage system 72 comprises at least one container 74 which has a bottom 74.1 and at least one outlet 74.2 offset upwards relative to the bottom 74.1.

[0037] This container 74 is configured to contain, in operation, the second liquid phase PL2, discharged from the foam collector 64, which has a third liquid surface SL3 separated from the bottom 74.1 by a distance (measured along the vertical direction) equal to that separating the bottom 74.1 and the outlet port 74.2. Thus, in operation, the third liquid surface SL3 is located at the same height as the outlet port 74.2 and the second liquid phase PL2 contained in the container 74 automatically exits by overflow through the outlet port 74.2.

[0038] The drainage system 72 also includes at least one continuous drainage conduit 76, without a valve or any other equipment for controlling the flow of liquid in the drainage conduit 76, positioned below the second enclosure 64.1 of the foam collector 64. A conduit is considered continuous if it does not include any element such as a valve, equipment for controlling the flow of liquid, a reservoir, or the like. This drainage conduit 76 is continuous between a first end 76.1 connected to the drainage port 64.2 of the foam collector 64 and a second end 76.2 located in the container 74 below the third liquid surface SL3. Thus, the second end 76.2 is separated from the bottom 74.1 by a distance less than that separating the bottom 74.1 and the opening 74.2. In operation, the second end 76.2 of the drain conduit 76 is always immersed in the second liquid phase PL2 present in the container 74.

[0039] According to a second embodiment shown in Figure 3, the drainage system 72 comprises at least one continuous drainage conduit 76, without a valve or any other equipment for controlling the flow of liquid in the drainage conduit 76, positioned under the second enclosure 64.1 of the foam collector 64. This drainage conduit 76 is continuous between a first end 76.1 connected to the drainage port 64.2 of the foam collector 64 and a second end 76.2, and at least one non-return valve 78 located at the second end 76.2 of the drainage conduit 76. For the purposes of this application, a non-return valve 78 is an element that allows the liquid to flow in only one direction, namely from the first end 76.1 to the second end 76.2, when the liquid pressure exceeds a certain threshold and blocks its return in the opposite direction.

[0040] Depending on the embodiment, the drainage system 72 comprises, extending from the drainage conduit 76 and after the non-return valve 78, a substantially horizontal straight section of conduit 82, a section of conduit 82' angled upwards, or a section of conduit 82'' incorporating a siphon, or any other section of conduit configured to maintain a liquid in the conduit section 82', 82'' in contact with the non-return valve 78 so that the latter is never exposed to air. This solution limits the risk of leakage at the non-return valve 78.

[0041] Regardless of the embodiment, the drainage system 72 includes at least one retention system 80 for a permanent liquid column of a second liquid height H76 in the continuous drainage conduit 76, the second liquid height H76 being equal to a distance measured in the vertical direction between the second and third liquid surfaces SL2, SL3 or between the second liquid surface SL2 and the second end 76.2 of the drainage conduit 76, the latter having a length suitable for containing this liquid column of height H76. According to the first embodiment, the retention system 80 includes a container 74 for retaining the second end 76.2 of the drainage conduit 76 in the second liquid phase PL2 present in the container 74. According to the second embodiment, the retention system 80 includes a non-return valve 78 located at the second end 76.2 of the drainage conduit 76.

[0042] The drainage system 72 includes at least one substantially vertical drainage conduit 76, positioned under the second enclosure 64.1 of the foam collector 64 to obtain gravity flow into the drainage conduit 76.

[0043] According to a particular feature, the second height of liquid H76 in the drain line 76 is between the first height of liquid H54 and the first height of liquid H54 + 30% of the first height of liquid H54.

[0044] According to one embodiment, the second liquid level H76 in the drain line 76 corresponds to the sum of the vacuum pressure (equivalent to the first liquid level H54) and a positive hydrostatic pressure H82, approximately equal to the first hydrostatic pressure H52 and on the order of 0.1 bar. Thus, the second liquid level H76 in the drain line 76 is approximately equal to the first liquid level H54 plus a height corresponding to a hydrostatic pressure on the order of 0.1 bar. To give an order of magnitude, the second liquid level H76 in the drain line 76 is approximately equal to the first liquid level H54 plus a distance of between 0.5 m and 1.5 m.

[0045] According to one configuration, the rising and falling column assembly 54 and the foam collector 64 are arranged so that the first and second liquid surfaces SL1, SL2 are substantially at the same height in operation.

[0046] According to this configuration, the third liquid surface SL3 or the second end 76.2 of the drain line 76 is located below the reservoir liquid surface SL52. The third liquid surface SL3 and the reservoir liquid surface SL52 are separated by a height substantially equal to the hydrostatic pressure H82.

[0047] During operation, when the second liquid surface SL2 exceeds a height, measured from the third liquid surface SL3, greater than or equal to the first liquid height H54 plus the hydrostatic pressure H82, the vacuum generated by the vacuum pump 62 in the second chamber 64.1 is insufficient to prevent the liquid from flowing into the drain line 76. The liquid then flows by gravity from the foam collector 64 to the second end 76.2 of the drain line 76. When the second liquid surface SL2 is below a certain threshold, the vacuum generated by the vacuum pump 62 in the second chamber 64 is sufficient to prevent the liquid from flowing into the drain line 76.

[0048] This solution allows for automatic control of the level of the second liquid surface SL2 in the foam collector 64 without moving components such as valves or pumps. It also reduces the costs of the treatment system and its maintenance.

[0049] According to the invention, a process for treating at least one liquid to be treated consists of storing said at least one liquid to be treated in at least one tank 52, said liquid having a tank liquid surface SL52 in the tank 52 and circulating said at least one liquid to be treated in at least one set of rising and falling columns 54 using a vacuum generator 62, the set of rising and falling columns 54 having a first enclosure 54.1 connected by a first conduit 68 to a second enclosure 64.1 of a foam collector 64 itself connected to the vacuum generator 62 by a second conduit 70.

[0050] During this circulation of the liquid to be treated, the first chamber 54.1 of the riser and downriller assembly 54 contains a first liquid phase PL1 with a first liquid surface SL1 and a first gaseous space 60 located above the first liquid surface SL1. The second chamber 64.1 of the foam collector 64 contains a second liquid phase PL2 with a second liquid surface SL2 and a second gaseous space 66 located above the second liquid surface SL2, a liquid phase PL2 being transferred by suction using the vacuum generator 62 from the first chamber 54.1 of the riser and downriller assembly 54 to the second chamber 64.1 of the foam collector 64.

[0051] The vacuum generator 62 is configured to obtain a first liquid height H54, measured in a vertical direction, between the liquid reservoir surface SL52 and the first liquid surface SL1.

[0052] To obtain automatic emptying of the foam collector 64, the latter includes at least one drain port 64.2 to which is connected at least one continuous drain conduit 76 between a first end 76.1 connected to the drain port 64.2 of the foam collector 64 and a second end 76.2, the drain conduit 76 having a length adapted to contain a permanent liquid column of a second liquid height H76 between the first liquid height H54 and the first liquid height H54 + 30% of the first liquid height, this liquid column being maintained in the drain conduit 76 by means of the vacuum generator 62.

Claims

DEMANDS 1. Device for treating at least one liquid to be treated comprising: at least one reservoir (52) configured to contain in operation said at least one liquid to be treated which has a reservoir liquid surface (SL52) in the reservoir (52), at least one set of riser and downramps (54) which includes: o a first sealed enclosure (54.1) configured to contain in operation a first liquid phase (PLI) with a first liquid surface (SL1) and a first gaseous space (60) located above the first liquid surface (SL1), o at least one vertical partition (54.2), positioned in the first enclosure (54.1), which delimits at least one riser (54.3) connected to the reservoir (52) and at least one downramp (54.4) connected to the reservoir (52), o at least one gas injection system (54.5) configured to inject at least one gas into the riser (54.3) at least one foam collector (64) comprising a second sealed enclosure (64.1) configured to contain, in operation, a second liquid phase (PL2) with a second liquid surface (SL2) and a second gaseous sky (66) located above the second liquid surface (SL2), the second enclosure (64.1) comprising at least one drain port (64.2), at least one vacuum generator (62) configured to generate, in operation, a first liquid height (H54) in the riser and downrrix assembly (54) equal to a distance measured in a vertical direction between the reservoir liquid surface (SL52) and the first liquid surface (SL1), at least one first conduit (68) opening into the first and second enclosures (54.1, 64.1) and configured to connect the first and second gaseous skys (60, 66), at least one second conduit (70) connected to the vacuum generator (62) and opening into the second enclosure (64.1), configured to connect the second gaseous sky (66) and the vacuum generator (62),. as well as at least one drainage system (72) comprising at least one continuous drainage conduit (76) between a first end (76.1) connected to the drainage port (64.2) of the foam collector (64) and a second end (76.2), characterized in that the drainage system (72) comprises at least one holding system (80) configured to maintain a permanent liquid column of a second liquid height (H76) in the continuous drainage conduit (76), the second liquid height (H76) being between the first liquid height (H54) and the first liquid height (H54) + 30% of the first liquid height.

2. Processing device according to the preceding claim, characterized in that the second liquid height (H76) in the drain conduit (76) is equal to the first liquid height (H54) increased by a positive hydrostatic pressure (H82) of the order of 0.1 bar.

3. Treatment device according to claim 1, characterized in that the second liquid height (H76) in the drain conduit (76) is substantially equal to the first liquid height (H54) increased by a distance of between 0.5 m and 1.5 m.

4. Processing device according to any one of the preceding claims, characterized in that the rising and falling column assembly (54) and the foam collector (64) are arranged so that the first and second liquid surfaces (SL1, SL2) are substantially at the same height in operation.

5. Processing device according to any one of the preceding claims, characterized in that the holding system (80) comprises at least one check valve (78) located at the second end (76.2) of the drain conduit (76), the second liquid height (H76) being equal to a distance measured along the vertical direction between the second liquid surface (SL2) and the second end (76.2) of the drain conduit (76).

6. Processing device according to the preceding claim, characterized in that the second end (76.2) of the drain conduit (76) is located below the surface of the liquid reservoir (SL52).

7. Treatment device according to any one of claims 5 to 6, characterized in that the drainage system (72) comprises, in the extension of the drainage conduit (76), after the non-return valve (78), a conduit section (82', 82'') configured to permanently maintain a liquid in the conduit section (82', 82'') in contact with the non-return valve (78).

8. Processing device according to any one of claims 1 to 4, characterized in that the holding system (80) comprises at least one container (74) configured to contain in operation the second liquid phase (PL2) discharged from the foam collector (64) and has a third liquid surface (SL3), the second end (76.2) being positioned below the third liquid surface (SL3), the second liquid height (H76) being equal to a distance measured along the vertical direction between the second and third liquid surfaces (SL2, SL3).

9. Processing device according to the preceding claim, characterized in that in operation, the third liquid surface (SL3) is located below the reservoir liquid surface (SL52).

10. Processing device according to any one of claims 8 to 9, characterized in that the container (74) comprises at least one outlet orifice (74.2), the third liquid surface (SL3) being located at the same height as the outlet orifice (74.2).

11. Processing device according to any one of the preceding claims, characterized in that the drain conduit (76) is substantially vertical and positioned under the second enclosure (64.1) of the foam collector (64) to obtain a gravity flow in the drain conduit (76).

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