FR2558925A1 - Drainpipe with a filter coating of natural fibres and method of manufacture - Google Patents

Abstract

The invention relates to a drainpipe 1 with a filter coating of natural fibres, particularly coconut fibres. The coconut fibre coating is according to the invention made resistant to rotting by the fact that a material which releases heavy-metal ions is combined with the coating material 2. For this purpose an endless filament, for example a copper wire 3 is incorporated into the coating or wound around the coating. Clearly, wires can also be made from an alloy which releases heavy-metal ions. The heavy-metal ions have a negative influence on the habitat of the bacteria responsible for rotting.

Description

 The invention relates to a drainage pipe with a filtering coating of natural fibers, in particular coconut fibers.

 The drainage pipes are fitted with filtering covers to prevent silting of the drainage pipe placed in the soil of the ground to be drained and to increase the hydraulic action. A siltation occurs when fine particles of the soil, especially in friable soils, are entrained by the water to be evacuated and can be deposited in the drainage pipe. The drainage pipes may eventually, after a fairly short time after installation, be blocked by siltation and no longer fulfill their function.

 It is known to provide drainage pipes with a permeable coating before laying them in the ground.

This permeable liner coating filters the entrained soil particles that cause siltation, before the water to be evacuated enters the drainage pipe placed in the solo
The usual materials for a filtering coating of drainage pipes are natural fibers such as sisal, straw, coconut fibers, wood shavings, etc. Natural fibers are good at a favorable cost but they present the disadvantage of rotting relatively quickly so that ultimately the desired filter effect is eliminated. M & e the coconut fibers, which are preferably incorporated because of their better resistance to rotting than other natural fibers, may eventually rot before that the risk of siltation of newly placed drainage pipes, for example after resting the soil shaken during installation, is eliminated.

 To avoid rotting of the coating, it is also known to add synthetic fibers which resist rotting well but at the same time increase the cost of drainage.

 The object of the invention is to make a coating for natural fiber drainage pipe resistant to rotting at a favorable cost.

 This problem is solved according to the invention by the fact that the coating comprises at least one endless bead of a material yielding heavy metal ions.

 Rots are caused by microorganisms, especially bacteria which, under favorable habitat conditions, relatively quickly destroy the natural fibers in the coating of a drainage pipe. By heavy metals, the habitat conditions for bacteria are deteriorated, because heavy metals have the effect of a poison on bacteria.

 According to the invention, the coating of natural fibers, for example coconut fibers, of a drainage pipe is combined with a cord made of heavy metal or of an alloy containing heavy metals. The natural fibers of the coating are thus protected from rotting in the vicinity of the bead. Rotting can at least be more or less delayed. During the implementation of the invention, a desired elimination or delay of rotting is regulated in a relatively simple way by the concentration of the disposition of heavy metals or of alloys containing heavy metals per unit area or by volume unit of a coating. We can thus finally make possible a controlled rotting evolution. Rotting is all the more delayed8 as the concentration of heavy metal avoiding rotting is high in the coating of natural fibers.

 A material yielding heavy metal ions can for example be a wire or a lattice, for example a braid, of heavy metal or of alloys containing heavy metals. A metal wire can for example be arranged in the simplest way in a spiral around the coating enveloping the drainage pipe, a desired density of a concentration of heavy metal which can be obtained by the pitch of the winding. The amount of heavy metal per unit area of the periphery of the coating is all the greater as the turns of the metal wire are closer together.

 This arrangement also has the advantage that the metal wire is used at the same time for fixing the coating on the drainage pipe. Obviously, it is also possible to use with a metal wire wires known per se or equivalent means used for fixing which are wound with the metal wires or at a distance from these wires around the coating.

It is also possible to place several metal wires around the coating. The application of the metal wires is carried out without problem and can be done with machines known for the application of a fixing wire around the coating without notable preparatory operations.

 However, it is also possible to place wires or screens during the manufacture of the coating and then place the coating provided with an incorporated metal wire on the drainage pipe.

 As a preferred material for the cord preventing or at least delaying rotting, copper is provided. your material can also be an alloy containing copper.

 By chemical and / or biological oxidation of divalent iron, the drainage pipes can form ochres.

 The arrangement according to the invention of the combination of a coating of natural fibers with materials yielding heavy metal ions still has, in addition to resistance against rotting, the additional advantage of avoiding biological oxidation of bivalent iron . Such biological oxidation and the resulting formation of ochres are also attributable to bacteria known as iron bacteria whose living conditions are negatively influenced by heavy metals. The arrangement according to the invention therefore not only avoids the rotting of a coating of natural fibers but also it prevents or at least delays advantageously a biological formation of ocher on the drainage pipe.

 An exemplary embodiment of the invention showing various features of the invention is shown in the accompanying drawing.

 This drawing shows in perspective a sectional view of a drainage pipe 1 which has an outer coating of coconut fibers 2. The coating is fixed externally by a copper wire 3 which is wound in a spiral around the coating.

Claims (5)

R E V E N D I C A T I O N S.  1. Drainage pipe with a filtering coating of natural fibers, in particular coconut fibers, characterized in that the coating (2) has at least one endless bead of a material yielding heavy metal ions.  2. Drainage pipe according to claim 1, characterized in that the cord is a metal wire (3) disposed around the coating (2).  3. Drainage pipe according to claim 1, characterized in that the cord is a metal wire incorporated in the coating (2).  4. Drainage pipe according to any one of the preceding claims, characterized in that the material for the cord is copper.  5. Method for manufacturing a drainage pipe according to any one of claims 1, 2 and 3, characterized in that at least one bead, preferably a metal wire (3) made of a material yielding heavy metal ions are wound on the coating (2) applied to the drainage pipe (1)