SK283429B6 - Elongated tubular product, such as in particular an installation conduct - Google Patents

Abstract

The invention concerns an elongated tubular product with the same cross section along its whole length, comprising a solid tube (1) made of at least a plastic material, both sufficiently flexible to be wound and unwound, and sufficiently rigid to resist a centripetal or centrifugal radial force, said solid tube comprising, on the inside and/or on the outside, a surface coating (3) whose free surface constitutes a friction surface and comprising a plastic matrix in which is distributed a lubricant. The invention is characterised in that, with synergistic effect, the particles (4) of a solid lubricant are distributed in the plastic matrix, at least partly flush at the free surface of the surface coating, and a liquid lubricant, compatible with the plastic matrix, is dispersed in the surface coating, practically without wetting the free surface of the latter.

Description

The invention relates to an elongate tubular article, in particular intended for plumbing conduits, having the same cross-section along its entire length in the longitudinal direction, consisting of a rigid pipe made of at least one plastic. This rigid tube is sufficiently flexible and flexible to be wound and unwound as well as sufficiently rigid to withstand centripetal and centrifugal radial forces.

It is clear from the generic definition that it is an object of the present invention to include, in one concept, equally well an installation conduit for one or more cables or one or more pipes that are subsequently disposed in the installation conduit, as a protective sheath for one or more cables, in particular for example electric cables.

Furthermore, the terms "cables" and "pipes" mean that the present invention is to be understood as referring to any pipeline conduit which generally permits the carrying or conveying of a particular stream, whether it be a liquid stream such as water or gas , o a stream of energy, such as electricity, or o other streams of information or signals, such as video transmission via optical cables, or o stream of data in the form of electrical signals, which may be analog, digital and the like.

BACKGROUND OF THE INVENTION

For purposes of presenting and defining the subject of the present invention, reference will now be made, by way of example, to plumbing conduits and / or cables, or pipes, or conduits installed in said plumbing conduits.

In order to limit the amount of engineering work, and in particular the number of connecting chambers, it is known to lubricate the friction surface corresponding to the inner surface of the rigid pipe forming the conduit and / or the outer surface of the protective sheath or sheath of, for example, the cable sheath. This in fact makes it possible to increase the length of the pipe, tube or pipe that can be installed.

This lubrication is usually performed by a coating on the inside and / or outside of the pipe, the free surface of which is a friction surface. A number of different solutions have been proposed for this purpose.

In accordance with the contents of WO 93/14546, the surface layer consists of a film or a coating of a lubricant, either in solid or liquid form. For example, the solid lubricant coating may be a plastic base material made of polyethylene in which solid particles, such as graphite particles, may be disposed. For example, the liquid lubricant coating may be a silicone oil.

EP 0 326 711 discloses a solution which is comparable to the above solution in that the rigid surface layer represents the inner layer of the extrusion tube together with the outer layer.

In accordance with the contents of DE 3,539,304, there is added a surface layer consisting of a grease or a paste having lubricating properties but adhering so that the surface layer remains inside the respective tube.

This lubricating paste or grease consists of a mixture of liquid lubricant and solid lubricant particles.

SUMMARY OF THE INVENTION

In accordance with the present invention, therefore, a tubular article has been developed, in particular for plumbing conduits having the same cross section along its entire length in the longitudinal direction, consisting of a rigid pipe 1 made of at least one plastic, the rigid pipe 1 being sufficiently flexible and flexible for winding and unwinding thereof, and sufficiently rigid to withstand centripetal and centrifugal radial forces, wherein the rigid tube 1 is provided on its inner side and / or on its outer surface with a surface layer 3 whose free surface forms a friction surface, wherein the surface layer 3 is formed of a plastic base material in which the lubricant is dispersed, on the one hand, the solid type grease particles 4 are disposed in the plastic base material, the particles 4 being at least partially aligned with the free surface area of the surface layer 3, and on the one hand, the lubricant is of the fluid type, Compatible with plastic base material, dispersed in surface layer 3.

The liquid lubricant is preferably silicone.

The liquid lubricant has a viscosity of at most 1000 centistokes at room temperature, in particular from 10 to 1000 centistokes.

The solid lubricant particles 4 are preferably microspheres having a diameter of at most 200 µm and in particular from 1 to 15 µm.

The rigid tube 1 consists of a plastic base material in which the dry lubricant particles 4 are disposed, the particles 4 being partially aligned with at least one inner or outer free surface 2 to form a dry friction surface.

The liquid lubricant is dispersed into the plastic, the outer surface and the inner surface of the base material being dry.

The liquid lubricant consists of an additive whose proportion is at least 0.02% by weight of the plastic base material, in particular from 0.02% to 0.08% by weight of the base material.

The proportion of solid lubricant to liquid lubricant is at least 5%, in particular between 5% and 20%, and preferably equal to 10%.

Accordingly, it is an object of the present invention to provide a tubular article with a permanent and almost dry lubrication of the friction surface or friction surfaces of a rigid tube, whereby the friction forces are substantially reduced compared to said solutions.

For this purpose, in accordance with the present invention, an interconnection of action has been found between, on the one hand, solid lubricant particles dispersed in a plastic base material, the particles being at least partially aligned with the free surface area of the coating, and on the other a liquid type lubricant compatible with the plastic base material dispersed in the surface layer without wetting the free surface area of the surface layer.

The observed effect of said interconnection can be explained by the fact that the solid lubricant particles that are aligned with the surface are as if subsequently lubricated with a liquid lubricant to moisturize them.

As a result of the present invention, the conduit duct becomes such that, without any further modification, it is compatible with all conventional and known plumbing techniques, whether pulling techniques used, for example, for small cables or blowing techniques, used, for example, with extension cables , or the techniques of priming and extrusion.

Furthermore, in the case where the solid lubricant is an electric conductor, the lubricant system of the present invention makes it possible to reduce at least partially the static voltage exerted by friction between the conduit and the cable when the cable is installed.

Thus, the present invention has the following secondary features:

the solid lubricant has a lamella structure, such as graphite, or further has a polymer structure with oriented long straight chains, such as polytetrafluoroacetyl;

the solid lubricant particles are microspheres having a diameter of at most 20 µm, preferably between 1 and 15 µm;

the liquid lubricant is preferably, but not exclusively, silicone; it has a viscosity of at most 1000 centistokes at room temperature, and preferably between 10 and 1000 centistokes, for example, wherein the thickness of the liquid lubricant film on the free surface area of the surface layer does not exceed 1 µm;

the solid lubricant is a filler;

the surface layer is irregular along the circumference of the rigid tube and corresponds, for example, to longitudinal ribs or grooves; but such the same surface layer may be continuous along the entire circumference of the fixed tube.

Preferably, it is a rigid pipe which consists of a plastic base material in which the dry lubricant particles are distributed, the particles being partially aligned with at least one inner or outer surface and thus represent a dry friction surface while the liquid liquid is dispersed therein. lubricant, without wetting or external surface or inner surface of the base material.

In accordance with a preferred embodiment of the invention, the solid lubricant is a filler having a proportion of at least 5% by weight of the amount of the plastic base material, in particular between 5% and 20% by weight of the base material.

In accordance with the same preferred embodiment of the present invention, the base material comprises in the dispersed state a liquid lubricant which is an oath having a proportion of at least 0.02% by weight of the amount of the plastic base material, and in particular lies between 0.02% by weight. and 0.08% by weight of the amount of the base material.

In this case, for example, the ratio of the solid lubricant to the liquid lubricant may be at least 5%, in particular between 5% and 20%.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference to the following examples, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic axial sectional view of an installation conduit according to the present invention;

Fig. 2 is a schematic axial sectional view of a cable protection housing according to the present invention; and FIG. 3 shows a schematic cross-sectional view of an installation duct according to the present invention, but in a slightly different embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the tubular article or installation pipe of the present invention consists of a rigid pipe 1 made of filled plastic (e.g. high density polyethylene) that is sufficiently flexible and flexible to be wound and unwound as well as sufficiently rigid to could withstand centripetal and centrifugal radial forces. This rigid tube 1 has a dry friction surface corresponding to its inner surface 2.

In accordance with the present invention, at least one surface layer 3 is formed in the rigid tube 1, the free surface of the surface layer 3 forming a dry friction surface or an inner surface 2. This surface layer 3 is formed of a base material of plastic corresponding to of plastic rigid tube 1, in which the solid lubricant particles 4 are disposed in the form of microspheres, the particles 4 being partially aligned with the free surface of the inner surface 2.

In accordance with another embodiment of the tubular article or installation duct of the present invention shown in FIG. 3, the installation conduit in question consists of three concentric layers 6, 7 and 8, which can be respectively made of different plastics. Specifically, the outer layer 7, the inner layer 6, to which the surface layer 3 is attached, and another middle layer or intermediate layer 8. The surface layer 3 is not continuous along the circumference of the rigid tube 1 and is provided with longitudinal ribs 9 or corresponding longitudinal adjacent grooves. .

However, this surface layer 3 can of course also be continuously continuous along the circumference of the fixed tube 1.

As shown in FIG. 3, the surface layer 3 is formed by spraying, scattering or diffusing a solid lubricant in the form of particles, mixed with a liquid lubricant, inside the solid tube 1 after its extrusion but still in the viscoelastic phase.

In this way, the solid lubricant and the liquid lubricant are incorporated into the base material of the rigid plastic tube 1, at least on its surface.

Example 1

The tube, made of high density polyethylene (HDPE), which has the commercial designation DAPLEN 4610 from the French company PCD, having an internal diameter of 27 mm and a thickness of 3 mm, is made by extrusion on a CMS60 machine from Cincinatti.

A suspension of polytetrafluoroethylene (PTEE) powder having the commercial designation UNILUB T3 from Uniflon having an average particle size of 16 µm in silicone oil having the commercial designation 47V100 from Pennwhite having a viscosity of 100 centistokes is sprayed in divided form at the outlet of a head of an extrusion die into the press tube while the tube is still viscoelastic. The polytetrafluoroethylene (PTFE) powder represents 20% by weight of polytetrafluoroethylene (PTFE) relative to the silicone oil.

The coefficient of friction between the inner surface of such a tube and the housing made of high density polyethylene (HDPE), having the same commercial designation as previously mentioned, is 0.075.

As long as everything remains the same, polytetrafluoroethylene (PTFE) powder and silicone oil act together to reduce the coefficient of friction because:

the coefficient of friction obtained without treatment of the inner surface of the tube is 0.19;

- the coefficient of friction achieved with the sprayed silicone oil is 0.102.

Example 2

The 8mm cable is blown with the extension into the 2400m plumbing duct, which is made of high density polyethylene (HDPE) and has an inner diameter of 26 mm and a thickness of 2.2 mm.

In the first case, the inner surface of the conduit is coated with the liquid lubricant (silicone oil) specified in Example 1.

In the latter case, the inner surface of the conduit is coated with a solid lubricant powder that is the same as in Example 1.

In the first case, it is not possible to install a cable whose length exceeds 400 m, while in the second case it was possible to install cables up to 700 m in length, with all the other circumstances being the same.

Example 3

An installation duct made of high density polyethylene (HDPE) having an inner diameter of 27 mm and a thickness of 3 mm was used to install a cable having an outer diameter of 17.6 mm, the inner surface of the installation duct being coated with silicone in the first case. oil having a viscosity of 100 centistokes, in the second case a Teflon® Teflon® powder having a particle size of 10 µm, and in the third case a powder mixture of the aforementioned silicone oil in an amount of 10% powder relative to the oil.

In the three cases, the coefficient of friction measured during extrusion and cable routing had the following respective sizes: 0.102.0.071, 0.0061.

Example 4

An installation duct made of high density polyethylene (HDPE) having an inner diameter of 27 mm and a thickness of 3 mm was used to install a 17.6 mm outer diameter cable, the inner surface of the installation duct being coated with a lubricant mixture consisting of a liquid lubricant (silicone) having a viscosity of 100 centistokes, and an increasing mass fraction of a solid lubricant (Teflon® Teflon® powder having the same particle size as in the previous case, the mass fraction in each case being 5.10) , 15 and 20% by weight.

In the four cases, the magnitude of the friction coefficients measured during the blowing and routing of the cable were as follows:

0,086

0.085 0.089 0.090.

Claims (8)

PATENT CLAIMS A tubular article, in particular for an installation conduit having the same cross-section along its entire length in the longitudinal direction, consisting of a rigid pipe (1) made of at least one plastic, said rigid pipe (1) being sufficiently flexible and flexible to its winding and unwinding as well as being sufficiently rigid to withstand centripetal and centrifugal radial forces, the rigid tube (1) being provided on its inside and / or on its outside with a coating (3) whose free surface forms a friction surface wherein the surface layer (3) is formed of a plastic base material in which the lubricant is dispersed, characterized in that, on the one hand, the solid type lubricant particles (4) are disposed in the plastic base material, the particles (4) being at least partially aligned with the free surface area of the surface layer (3), and on the other hand the lubricant of the fluid type is compatible with positive material of plastic, dispersed in the surface layer (3). The tubular article of claim 1, wherein the liquid lubricant is silicone. The tubular article according to claim 1, characterized in that the liquid lubricant has a viscosity of at most 1000 centistokes at room temperature, in particular from 10 to 1000 centistokes. The tubular article according to claim 1, characterized in that the solid lubricant particles (4) are microscopic spheres having a diameter of at most 20 µm and in particular of 1 to 15 µm. A tubular article according to claim 1, characterized in that the rigid tube (1) consists of a plastic base material in which the dry lubricant particles (4) are disposed, the particles (4) being partially aligned with at least one internal or an external free surface (2) to form a dry friction surface. The tubular article of claim 5, wherein the liquid lubricant is dispersed into the plastic, wherein both the outer surface and the inner surface of the base material are dry. A tubular article according to claim 6, characterized in that the liquid lubricant consists of an additive at least equal to 0.02% by weight of the plastic base material, in particular from 0.02% to 0.08% by weight of the base material. . The tubular article according to claim 7, characterized in that the proportion of solid lubricant to liquid lubricant is at least 5%, in particular lies between 5% and 20%, and preferably equal to 10%.