FR2476168A1 - FLEXIBLE FLOATING DAM HAVING VARIABLE RIGIDITY TRANSVERSE STIFFENERS - Google Patents

Abstract

FLEXIBLE FLOATING DAM CONTAINING TRANSVERSAL STRAIGHTENERS WITH VARIABLE RIGIDITY. THIS DAM IS CHARACTERIZED IN THAT THE STRAIGHTENERS 4, 5 ARE ADAPTED TO TILT TO THEIR LOWER PART 4B, 5B BY GETTING AWAY BEFORE THE CURRENT FOR A SUFFICIENT SPEED THEREOF, THE RIGIDITY OF THIS LOWER PART DECREASING PROGRESSIVELY FUR AND AS WE APPROACH THE LOWER EDGE OF THE DAM. THE INVENTION IS IN PARTICULAR APPLICABLE TO THE FIGHT AGAINST AQUATIC POLLUTION.

Description

The present invention relates to a flexible floating barrier comprising

  transverse stiffeners with variable rigidity. This dam is particularly usable for delimiting navigation zones, or water bodies intended for nautical activities such as, for example, swimming, or

for aquaculture.

  A very important application of the invention is

  the fight against aquatic pollution by solid waste

  floats, or by chemicals, more specifically

primarily by hydrocarbons.

  The dam according to the invention may be used at fixed position, stretched between two mooring points, or in the manner of a net or trawl, be attached at its ends to one or more towing vessels to clean a

polluted water.

  A first type of dam is already known

  as a floating pudding to which is attached a weighted skirt

  by a chain at its lower part. Tracing efforts

  tion exerted on such a dam are applied to the weighting line and / or to a cable attached to the dam. A disadvantage of such a dam is that in a strong current the skirt is hollow and the water rises on the upstream side of the dam, which

  causes a reduction in the emergent height of the dam.

  The polluting products may then pass over

the pudding.

  When the current is very strong, the dam can

  even be completely drowned, the water then passing over.

  There is a second type of dam, which has a flexible barrier structure with stiffeners

  cross-sections to which floats adapted to

  hold in the water this flexible structure in a sensible position

  vertically, to create a screen. These dams have the advantage of maintaining a constant emergent height, but as the intensity of the current increases

  increases, they go to bed and can even rotate a half

turn around a horizontal axis.

  The stability of such a dam can be improved either

  by providing it with a ballast, which has the disadvantage of

  to bring out its inertia and, consequently, to compromise its response to the waves, either by moving the floats away from the plane of the barrier, so as to increase the righting torque, since these floats are arranged on one side or on both sides

of the barrier.

  It is known, on the other hand, that above a certain speed of current (1 node approximately), the dams can no longer retain pollutants that pass under the dam, either by entrainment or by vortex effect

  (training of the water table under the dam in the form of

  droplets that rise to the surface downstream of the dam).

  A first object of the invention is to provide a

  dam that can maintain a significant emergent

  constant when the speed of the current increases and up to the limit value of this speed corresponding to the appearance of phenomena of leakage of pollutants under the barrier, this dam being otherwise able to maintain its vertical position without being destroyed or knocked down for current speeds above the limit value

  above, in order to recover fully

  its barrier function vis-à-vis the pollutants as soon as the speed of the current becomes lower than said limit value. A second object of the invention is to provide a

  -booting that can be easily stranded so as to

  see being used in tidal areas. Floating-type dams mentioned above are easy to fail, their skirts spreading over

  the ground when the floating pudding comes to rest on it.

  However, in this position, the flexible skirt is covered with

  sand, or pebbles, by the play of waves and

  bag, which, by the combined action of the weight of the materials

  covering the skirt and the suction effect of this

  on the ground, leads, at the time of the ascent of the

  water, significant efforts at the connection between the flange and the skirt, these efforts may lead to

breakage or tearing.

  The objectives mentioned above can be

  in accordance with the invention, with a floating barrier

  carrying a flexible barrier structure provided with vertical stiffeners to which are attached floats adapted to support this flexible structure in water in a substantially vertical position, characterized in that these

  stiffeners are adapted to bow to their lower part

  fading away from the current for sufficient speed

  health of it, without causing any significant change

  tilt on the water of the rest of the dam.

  According to a particular embodiment, said stiffening elements are arched at their lower part, in the absence of force applied to these elements, in a

  substantially perpendicular to the surface of the bar

rage.

  The dam will then advantageously comprise or-

  Ganes supporting the flexible barrier structure in a substantially vertical position when the dam is out of the water (dry, or beached), in a position such that the curved lower end of the stiffening elements

rests on the ground.

  Examples of embodiments according to the invention are illustrated by the appended figures, in which: FIG. 1 is a diagrammatic perspective view of the flexible structure forming a barrier and of stiffness stiffeners of a dam according to the invention; FIGS. 2A, 2B, 2C and 2D show diagrammatically this cross-sectional dam at the right of a stiffener, for increasing speeds of the current,

  FIG. 3 schematically illustrates, in cross section,

  the, a dam according to the invention easily strandable,

  FIG. 4 illustrates a mode of fixing elements of

eg stiffeners.

  FIG. 1 shows, in partial view, a barrier according to the invention comprising a flexible barrier structure consisting of a flexible skirt 1 and an armature comprising longitudinal elements with a high tensile strength, which can advantageously be constituted by of the

  ribbons 2 in armed matter and transversal elements

  which maintain a predetermined spacing between the longitudinal members, which transverse members may

  to be constituted by ribbons 3 of the same nature as the ru-

bans 2.

  These ribbons may, for example, be constituted

  of one, trig in plastic material, reinforced by a reinforced

  made of high-strength filament, such as metallic yarns

  5% of glass yarn, carbon fibers, or plastic yarns such as those used in

  textile industry (polyamide, polyester, etc ...).

  The frame can be formed by welding together

  61emts 2 and 3 or by weaving these elements.

  The dam also includes transitional stiffeners

  Q versaux each of which is formed of two profiled elements 4 and plags on both sides of the frame that they press between them and possibly the skirt 1, being together

  pgr BQUloDS or rivets 6, or by any other means of ser-

rage.

  The continuity of the resistance frame to the trac-

  tion is thus not interrupted to the right of the stiffeners which are thus subtracted from the tensile forces applied to the

  dam, these efforts being supported by the only frame.

  Floats 7 and 8 are combined with the

4 and 5 by arms 9 and 10.

  In the invention, the stiffeners are constituted so that their rigidity gradually decreases at their lower part, as one approaches the lower edge 11 of the barrier, this lower part

  stiffeners being otherwise elastic.

  The profiled elements constituting the stiffeners

  may, for example, have a rigid upper

  formed of the elements 4a and Sa at the lower end of the

  which will be fitted with flexible lower elements

  and Plastics 4b and 5b whose rigidity decreases progressively-

  down. The elements 4b and 5b will, for example, consist of an elastic material such as polyurethane, polychloroprene, an armed plastic material, etc. The thickness or section of these elements 4b and 5b may, for example, gradually decrease. as we get closer to the lower edge of the dam, to achieve the

variable rigidity desired.

  In a general manner, the elements 4b and Sb will be made of an elastic material resistant to water and

  polluting products that must be stopped by the dam.

  These different profiled elements pressing between them the frame and the skirt may, for example, be joined by

  rivets made of nylon, stainless steel or gal-

  vanized1to prevent corrosion in the water.

  We can also join these elements by gluing

or by welding.

  According to a preferred embodiment, the stiffener elements 4b, 5b will have at rest a pre-camber in the absence of force applied to these elements in a direction substantially perpendicular to the surface of the flexible barrier structure. Figure 2A shows schematically

this arch of radius R at rest.

  The use of stiffeners with variable rigidity allows a progressive deformation of the skirt, as the forces due to the current increase, as shown in FIGS. 2A, 2B, 2C and 2D, the elements of

  stiffeners 4b and 5b gradually recovering under the ef-

  fet of the current. The rigidity characteristics of these elements

  can be calculated so that the lower part of the stiffener becomes substantially upright for

  the limiting speed of the current: beyond which the bar-

  ge can no longer ensure its barrier function vis-à-vis pollutants and ends up bending in the direction

  opposite to that of the initial camber of Figure 2A,

  that the speed of the current becomes greater than this value-

  limit - (Fig. 2D). There is then a valve effect allowing the water to pass under the skirt when the speed

  current exceeds that limit speed, without any delay

  the dam or even incline it significantly on the vertical

the.

  The dam thus retains its function of vis-

  polluting products up to the speed limit of the

  current; it is not damaged for flow speeds.

  for whom, in any case, the

  retention of pollutants can no longer be ensured and it covers this function when the speed of the current becomes lower than the said limit value, thanks to the elasticity of the lower part of the stiffeners which

  then rectify by resuming one of the configurations

2A to 2C.

  The space separating the flexible elements 4b and Sb of the stiffener corresponds to the "neutral fiber" of this stiffener, along which no tensile stresses or compressive stresses are exerted during the deformations of this bending stiffener (FIGS. 2A to 2D). Therefore, there will be no risk of tearing of the skirt 1 during these deformations if it is pressed with the armature (2, 3) between

the elements 4a, 4b and Sa, Sb.

  However, in order to facilitate repairs of the skirt 1, it may be advantageous to constitute the latter with successive elements each of which comprises at its ends a flexible strip 15 (FIG 4) on which the skirt is connected so as to be welded on itself. This wand

  is engaged in means of restraint carried by the stiffeners

  2476t68, such as, for example, the tube 16 welded to the element and having the longitudinal slot 17 for the passage of

the skirt 1.

  As regards the problem of stranding of the dam, the use of stiffeners with variable stiffness can provide an interesting solution. Indeed, if we give to

  the lower part of these stiffeners a camber to the re-

  pos (radius of curvature R, Fig. 2A), this camber will be accentuated

  killed at the time of the grounding due to the weight of the dam itself. By adjusting the height of the dam above the ground level by suitable means, the radius of curvature r

  what will the stiffener take then may remain in limi-

your acceptable.

  Under these conditions (Fig. 3), the skirt will rest on the ground by its lower edge without being completely lying down and this lower edge will be completely kept in contact

  with the ground by the spring effect due to the stiffener.

  This will eliminate the risk of burial

  skirt of the skirt mentioned above about dams

  and thanks to this provision, the dam will remain

  to polluting products throughout the period of the

  low tide, as well as at the beginning of the rise of the flow.

  By way of non-limiting example, the stiffeners

  may be calculated so as to have a radius of

  resting-between 0.5 and 1 meter and so

  be straightened up to a vertical position for quick

  its current of the order of 0.8 to 1 knot, which will give

  at the dam its maximum draft in the vicinity of the

  is limited-retention of hydrocarbons. For current speeds greater than about 1 node, the stiffeners will gradually bend to the opposite side to their initial curvature (Fig. 2D). When the speed of the current decreases, the stiffeners, which are made of an elastic material

  will gradually resume their arched initial shape

lustred by Figure 2A.

  In order to facilitate the stability and the holding of the dam during its stranding, it is preferable, without being limiting, that the floats 7 and 8 are arranged on either side of the dam (catamaran type dam),

  these floats being provided with appropriate means (skates,

  or wheels 12, 13, FIG. 3) to rest on the floor in

sition failed.

  In addition, the face of the stiffeners which comes into con-

  tact with the ground during the stranding will be advantageously

  protection devices 14 (pads, skates or

  rope) to reduce the risk of chafing

these stiffeners on the floor.

  These devices will also facilitate deployment

  and the implementation of the dam when it is launched.

  For the implementation of the dam, it will be possible

  two cases a) if you want to block a river such as a river, the dam will be advantageously arranged so that the stiffeners have their concave face on the upstream side of the river, b) when the dam will be used to protect a tidal coast or estuary in which the current has an alternating direction, the dam will preferably be

  arranged so that the stiffeners present their

  concave side to the side where pollution comes from (general

the sea).

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Claims (17)

R E V E N D I C A T I 0 N S   1. - Floating barrier with flexible structure   barrier mantle equipped with vertical stiffeners to which are   floats adapted to support this flexible structure.   in the water in a substantially vertical position,   rised in that these stiffeners are adapted to tilt at their lower part by fading in front of the current for   speed of the latter without causing a change in   significant improvement in the inclination of the rest of the bar   rage. 2. - Floating dam according to claim 1, characterized in that, at least at their lower part, these stiffeners   are elastic with a rigidity that decreases progressively-   as we get closer to the lower edge from the dam.   3. - Floating barrier according to claim 2, characterized in that the thickness or the section of the lower portion of the stiffeners gradually decreases as and when   as we approach the lower edge of the dam.   4. - Floating barrier according to claim 2, characterized in that the stiffeners have a rigid upper part   and a flexible and elastic lower part.   5. - Floating barrier according to claim 2, characterized in that said flexible and resilient lower part is embedded in said rigid upper part at the end. lower of the latter. 24761-68   6. - Floating dam according to one of claims 2 to 5,   characterized in that said stiffening elements are cambered   resting at their lower part, in a trans-   versal with respect to the direction of elongation of the dam.   7. - Floating barrier according to one of claims 2 to 6,   characterized in that the lower portion of the stiffeners is made of polyurethane.   8. - Floating dam according to one of claims 2 to 6,   characterized in that the lower portion of the stiffeners is made of polychloroprene.   9. - Floating dam according to one of claims 2 to 6,   characterized in that the lower portion of the stiffeners is made of reinforced plastic material.   10. - Floating dam according to one of the preceding claims   characterized in that said flexible structure   wears a flexible frame that is resistant to traction.   11. - Floating barrier according to claim 10, characterized   in that said armature is constituted by ribbons   flexible with high tensile strength.   12. - Floating dam according to claim 10, characterized   in that each of said stiffeners is formed of two   elements placed on either side of the frame feel between them.   13. - Floating barrier according to claim 10, wherein   the flexible barrier structure comprises a hollow skirt   ple, characterized in that this skirt is pressed between   said elements forming the stiffeners.   14. - Floating barrier according to claim 1, wherein the flexible barrier structure comprises a skirt.   flexible, characterized in that said skirt is formed of   each having at its ends a rod to which is attached the skirt element, the rod being adapted to engage in retaining means carried by the stiffeners.   15. - Floating barrier according to claim 6, characterized in that it comprises means for supporting the flexible barrier structure in substantially vertical position   when the dam is out of the water, in such a position   the lower arched end of the stiffeners rests On the ground.   16. - Dam according to claim 15, characterized in that said means comprise rollers, pads or wheels equipping the floats.   17. - Dam according to claim 6, characterized in that   the stiffeners comprise at their lower part   yens of resistance to abrasion, on the side of these stiffeners intended to come into contact with the ground when the dam is out of the water. 2,476 16 8 1 2