FR2792664A1 - Freshwater collection assembly from a karstic well, spring or outlet, utilizes a wide bore pipe inserted into the well bore in a sealed manner - Google Patents

Abstract

The collection assembly comprises of a main bore pipe attached and sealed to a freshwater outlet (17) within a karstic well. The bore pipe is connected to a capture chamber (14) and controlled by a flow regulator (10) and pressure and salinity sensors (12,13). A flood spillway (18) is provided.

Description

The present invention relates to a device for collecting water, in a

  flooded karst pipe (for example, a

  submerged cave gallery) or a submerged outlet (for example5 an underwater source), allowing controlled water pressure upstream of the catchment.

  It also relates to a method for implementing the device.

  Water abstraction in karst massifs is traditionally done either by the installation of a pump in a karst drain or by water diversion using a work barring an outlet or the course of a river

  underground and directing the water towards a collection pipe.

  The installation of catchment systems often requires having to cut off the water flow in order to be able to

  make the necessary seals.

  The device of the present invention allows the completion of sealing works in a water flow and it then allows the loading of water inside the rock mass, which makes it possible to raise the level of the water table.

  aquifer and thereby increase the water pressure at the outlet.

  In the case of terrestrial sources, this allows a rise of the water in the karstic cracks thus authorizing a storage of the water inside the rock mass and a

  increased water pressure at the outlet.

  In the case of coastal and underwater sources, this pressurization by total obturation allows in particular:

  - an increase in the load of the freshwater table over-

  above the freshwater / seawater interface, allowing its

migration down.

  - a reduction in the effects of seawater suction upstream

outlets.

  These two combined effects make it possible to overcome partially or even completely the residual salinity of this type of emergence, salinity which currently considerably exploits them. The present invention relates to a method of capturing fresh water at a karst outlet characterized in that - we introduce channeling means into the outlet - we close the outlet around the channeling means in order to put in charges water upstream of the catchment in a controlled manner. It also relates to a device for collecting fresh water at a karst outlet, capable of implementing the method characterized in that it has: - means for channeling the flow of water from the outlet - means for closing the outlet around the channeling means in order to load the water upstream of the collection in a controlled manner. The method and the device presented here can be presented in the embodiments set out below: - a tube is used as channeling means - the outlet is closed by: - placing on the periphery of the tube two annular balloons suitable for delimiting a central chamber - insertion into the central chamber of means for injecting a sealant and of means for evacuating the water present in the central chamber - inflation of balloons to make the central chamber watertight - evacuation water from the central chamber and

injection of sealant.

  - it is used in a submerged outlet from an underwater or coastal source in order to reduce or eliminate the residual salinity of the emergence by controlling the flow of

  water in the channeling means.

  - the channeling means are a tube - the sealing means comprise: - at least two inflatable annular bladders placed around the periphery of the tube and delimiting a central chamber - means for discharging the water present in the chamber central - means for injecting a product of

  sealing in the central chamber.

  The catchment device comprises a discharge of floods in the form of a substantially vertical tube opening at its

  low end on the channeling means.

  It includes means for adjusting the flow of water in

the means of channeling.

  The means for adjusting are a bladder internal to the channeling means and capable of being inflated or deflated for

control the flow.

  It includes means for measuring the pressure and the salinity of the water in the pipe means, for

control, as a function, the flow.

  The device comprises according to a first characteristic: - a tube placed in the outlet or the karstic conduit, collecting the entire flow, this tube will be sealed in a sealed manner to the walls of the conduit or the outlet, - a valve then fixed to this tube and making it possible to reduce or even cancel the flow rate, - a water collection pipe downstream of the valve, connected to the water distribution system, - pressure and salinity sensors intended to monitor the evolution of the system, - an electronic device allowing the flow to be adjusted as a function of the salinity by controlling the valve, - a spillway, depending on the geometry of the conduit, it can be installed

several tubes.

  The attached drawings are given as indicative and non-limiting examples. They represent different modes

  preferred embodiments according to the invention.

  Figure 1 shows in section a general device for

capture.

  Figure 2 shows in section the detail of the tube to be sealed.

  Figures 3 to 5 show the sealing process with: - Figure 3: installation of the sealing tube and inflation of the balloons - Figure 4: injection of the sealant - Figure 5: fixing the valve Figure 6 shows in cuts an inflatable flow restrictor. The channeling means can be a tube 1 capable of

be sealed.

  The tube 1 to be sealed may include a flange 2 allowing the attachment of the remainder of the device with the aid of screws and nuts. This tube 1 may be provided with two inflatable annular bladders 3 intended on the one hand to seal the duct and ensure sealing, and on the other hand to isolate a central chamber 4 into which a sealant 5 will be injected in order to ensure a tight and permanent sealing of tube 1, they can be glued to tube 1 or placed

  between four annular shoulders 6.

  The balloons 3 thus participate in the sealing means.

  The sealant 5 may be a cement or a resin. The balloons 3 could be made of elastic material (rubber for example) or not (PVC, coated nylon for example), their shape could be circular or adapted to the shape of the duct to be closed. They can be inflated with air or with a fluid of any kind. They will be fitted with inflation hoses 7 fitted with inflation tips which may be of the "direct-system" type used in scuba diving. Additional balloons may be provided for

ensure total tightness.

  After checking for leaks, the central chamber 4 can be filled with a concrete or resin grout around the tube, between the two inflatable rings, using two or more rigid tubes 8 put in place before inflation. balloons, some will be used for the injection of the grout, the others will allow the evacuation of the water contained in the

  chamber 4 and checking the filling.

  On the tube 1 thus sealed, a collection pipe 9 fitted with a flow reducer 10 will be fixed. This reducer may be a tube of smaller cross section, a plate ensuring partial closure of an internal inflatable balloon 11 or a valve. The valve may be electric and controlled from the surface. A pressure sensor 12 intended to monitor and control the pressurization will be installed upstream of the reducer. The device may be fitted with an electronic regulation system intended to automatically adjust the

  flow rate of the device so as to maintain zero salinity.

  The electric valve or the inflatable balloon can then be controlled by computer according to the data supplied by a salinity sensor 13. When the salinity is too high

  high, the computer controls the closing of the reducer 10.

  The device may be provided with a spillway 13 installed upstream of the reducer 10. It is characterized by a tube of sufficient diameter to allow the passage of water and of a sufficient height to allow

  in normal times to counter the pressure of fresh water.

  The success of the operation may involve identifying and plugging additional karst drains through which either a fresh water leak or a seawater suction could take place. A similar device (tube to be sealed and balloons) can be used. The tube, once sealed, can either be fitted with a valve or fitted with a tight plug. This plug could be a plate fixed by

  several long screws and nuts.

  The sealing of the tube placed in the outlet or the sealing of the other points, can be done by placing pockets of fabric filled with quick-setting cement taken from the sea. These pockets, of variable size, will be contained in

  waterproof plastic pockets that will be opened underwater.

  The infiltration of water through the fabric will allow the setting of the cement, the diffusion of a small part of the cement through

  the fabric allowing the connection between the successive pockets.

  The collecting pipe 9 can lead to a chamber

  of collection 14 in which the water pumping will be carried out.

7 2792664

REFERENCES

  1. Tube 2. Flange 3. Ball 4. Central chamber 5. Sealant 6. Annular shoulder 7. Inflation hose 8. Injection and evacuation tubes 9. Collection hose 10. Flow reducer 11. Ball internal 12. Pressure sensor 13. Salinity sensor 14. Collection chamber 15. Water 16. Rock mass 17. Karstic drain 18. Spillway

Claims (10)

  1. Method for capturing fresh water at a karst outlet characterized by the fact that - we introduce channeling means into the outlet - we close the outlet around the channeling means in order to load so upstream water control of the catchment.   2. Collection method according to claim 1 characterized in that - a tube (l) is used as channeling means - the outlet is closed by: - placing on the periphery of the tube (1) two bladders ( 3) annulars capable of delimiting a central chamber (4) insertion into the central chamber (4) of means for injecting a sealing product (5) and of means for discharging the water present in the central chamber - inflating the balloons (3) to make the central chamber watertight (4) - evacuation of the water from the central chamber (4) and   injection of sealant (5).   3. Collection method according to any one of   claims 1 or 2 characterized by the fact   that it is implemented in a submerged outlet from an underwater or coastal source in order to reduce or eliminate the residual salinity of the emergence by controlling the flow of   water in the channeling means.   4. Device for collecting fresh water at a karst outlet, capable of implementing the method according to one of   claims 1 to 3 characterized by the fact   that it has: - means for channeling the flow of water from the outlet a - means for closing the outlet around the channeling means in order to charge the water upstream of the capture. 5. Collection device according to claim 4 characterized in that - the channeling means are a tube (1) - the sealing means comprise: - at least two inflatable annular bladders (3) placed around the periphery of the tube (1) and delimiting a central chamber (4) - means for discharging the water present in the central chamber (4) - means for injecting a sealant into the central chamber (4).   6. Collection device according to claim 5 characterized in that the injection and evacuation means are tubes (8), the end of which is introduced into the central chamber   (4) before inflating the balloons (3).   7. Collection device according to any one of   claims 4 to 6 characterized by the fact   that it comprises a spillway (18) in the form of a substantially vertical tube opening at its lower end onto the means of channeling.   8. Collection device according to any one of   claims 4 to 7 characterized by the fact   that it includes means for adjusting the flow of   water in the channeling means.   9. Collection device according to claim 8 characterized in that the means for adjusting are an internal bladder (11) to the channeling means and able to be inflated or   deflated to control the flow. 2792664   10. Collection device according to any one of claims 8 or 9 characterized in that   that it includes means for measuring the pressure and the salinity of the water in the channeling means, to control, as a function, the flow rate.