SI20133A - Elongated tubular product, such as in particular an installation conduit - 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

EXTENSION PIPE PRODUCTS SPECIFICALLY FOR

INSTALLATION WATERS

The present invention relates to an elongate tubular product having a generally uniform cross section along its entire longitudinal direction, and comprising a rigid tube composed of at least one type of plastic that is sufficiently flexible to be bent, unwound, and suitably rigid to can transmit centripetal or centrifugal forces.

In view of the above general definition, it can be understood that the present invention can be used as a protective sleeve as well as the installation conduit for one or more cables, or for one or more pipes subsequently inserted into said installation conduit to protect one or more cables , such as power cables. Moreover, according to the term cable and tube, it can be understood that the present invention covers all types of lines, which generally allow the transmission or transport of fluid flows (eg water or gas), energy (eg electrical), information signals (eg transmission) video signals via optical cables), or data in the form of electrical signals, whether analog, digital, etc.

For the presentation and definition of the present invention, details are provided with embodiments of installation lines and / or the installation of cables or pipes in such installation lines. In order to limit the amount of construction required, in particular the number of coupling chambers, it is known to lubricate a friction surface that rests on the inner surface of a rigid pipe that forms the installation conduit and / or other surfaces of the protective tube, e.g. shielding cable for cables. This basically allows for an increase in the length of pipes or cables that can be installed in the installation duct. This lubricant is generally provided in the form of a surface layer on the inner and / or outer side of the tube whose free surface forms the desired friction surface. Different solutions are proposed for this purpose.

According to document VV093 / 14546, the surface layer consists of a lubricating film or a coating in solid or liquid form. In the case of a solid lubricating coating, this can be e.g. plastic mold made of polyethylene in which solid fragments are arranged, e.g. graphite fragments. In the case of a liquid lubricant, this can be e.g. silicone based oil. EP-0326711 discloses a solution comparable to the one presented above in that the solid surface layer forms the inner layer of the tube extending into the outer layer. According to document DE-3539304, there is a grease or paste surface layer which is lubricating but sticky and is added or applied to the inside of the tube.

This lubricant paste or grease consists of a mixture of liquid lubricant and particulate matter. The object of the present invention is a tubular expansion product with continuous, almost dry lubrication of the friction surface or the surface of the solid tube, with a significant reduction in the friction forces, compared to those present in the solutions discussed above.

For this purpose, in the light of the present invention, a reciprocal interaction is detected:

- on the one hand, lubricant particles of a solid type disposed in the plastic form of a surface layer and at least partially dispersed over the free surface of that layer; and

- on the other hand, a lubricant of a liquid type, united in a plastic form, the lubricant of which is effectively distributed to the surface of the layer without wetting its free surface.

is By way of the present invention, the installation line becomes, as such, a generally (universally applicable) line in terms of its compatibility with all the latest achievements of the installation technique, without any necessary special modifications, be it a draw technique, e.g. when using small cables, or blowing technique, e.g. using a weak or casting mold, or for the blowing and pushing technique.

Moreover, when the solid lubricant is also an electrical conductor, the lubricating system of the invention is capable of at least partially eliminating or eliminating the static charge generated by rubbing between the installation line and the cable during its installation or installation.

The present invention therefore has the following secondary characteristics:

- a solid lubricant is used, e.g. graphite having a laminar structure or other lubricant having a polymeric structure with oriented long straight chains, e.g. polytetrafluoroethylene;

- the fragments of the solid lubricant are microscopically small and up to a maximum diameter of 20 μηη and preferably between 1 and 15 μηι;

- liquid lubricant is preferred, not exclusive, to silicone; its viscosity at room temperature not exceeding 1000 mm ² / S and e.g. for viscosities between 10 and 1000 mm ² / S, the thickness of the liquid lubricant film on the free surface of the surface layer does not exceed 1 μπι;

- solid lubricant forms or. serves as a filler between layers;

- the surface layer is unevenly encircled by the volume of the solid tube and matches, e.g. with longitudinal ribs or grooves in the tube; as it is, this surface layer can be continuous throughout the entire length of the solid tube.

Preferably, in this embodiment, a solid tube having at least a plastic form in which, on the one hand, particles in the dry lubricant may be partially dispersed in at least one, internal or external free surface, and, on the other hand, is in the same a plastic mold can be effectively distributed liquid lubricant without wetting the free surface, either on the outer or inner surface of that plastic mold.

In view of this preferred embodiment of the invention, a solid lubricant forms a kind of filler whose weight ratio compared to the plastic form is at least 5%, and most preferably when this weight ratio is between 5% and 20% with respect to said plastic form. In this preferred embodiment of the invention, the plastic form comprises, in its dispersed state, a liquid lubricant forming an additive therein, proportional to the weight of at least 0.02% by weight of the plastic form, in particular or preferably between 0.02% and 0.08% by weight against this form. In this case, depending on the embodiment, the ratio of solid to liquid lubricant is at least 5%, in particular or preferably between 5% and 20%. The present invention will now be described with reference to the accompanying drawings, where:

Fig. 1 Fig. 2 Fig. 3 schematically shows in cross-section in axial direction the installation line of the invention;

shows a shielding cable for securing a cable according to the invention in cross-section in axial direction;

shows the installation line of the invention in cross-section but in a different assembly or. implementation case.

With reference to Figure 1, a rigid conduit 1 is made of compressed plastic (such as high specific gravity polyethylene) sufficiently flexible to bend and unwind and sufficiently rigid to withstand centripetal and centrifugal radial loads. This rigid tube has a dry friction surface that fits in properly with its inner surface.

According to the present invention, it is; at least one surface layer 3 is formed in solid tube 1, whose free surface of the surface layer 3 forms a dry friction surface (inner surface 2). This surface layer is formed by a plastic mold that corresponds formally to the solid tube and in which microscopic particles 4 of the solid lubricant are arranged, with these particles partially dispersed in the free surface 2.

In view of the following embodiment or embodiment of the insulation conduit of the invention shown in Figure 3, the latter consists of three concentric layers 6, 7 and 8, optionally made of suitable different types of plastic, namely outer layer 7, inner layer 6, in which is a combined surface layer 3 and another, middle or intermediate layer 8. The surface layer 3 is unevenly distributed over the circumference of the solid tube 1 and has e.g. is the longitudinal ribs, or the corresponding longitudinal adjacent furrows. However, of course, this particular surface layer is spread over the entire circumference of the solid tube 1.

The surface layer 3 is obtained by spraying or spraying the inside of the tube 1 with liquid lubricant mixed with solid lubricant in the form of fine particles after their removal in a viscous elastic phase.

In this way, solid lubricant and liquid lubricant are incorporated into the plastic tube form, at least on the surface.

EXAMPLES:

The tube is made of high specific gravity polyethylene (HDPE), (commercial name DAPLEN 4610 manufactured by the French company PCD), which has an inside diameter of 27 mm and a wall thickness of 3 mm, is injection molded on a production machine

Cincinati brand CM560.

Suspension (homogeneous dispersion of solids in liquid) of polytetrafluoroethylene powder, (UNILUB T3 commercial name of Uniflon manufacturer) with an average particle size of 16 pm, in io silicone oil (commercial name 47V100 of Pennwhite manufacturer) with a viscosity of 100 mm ² / S, is separate injected at the outlet of the outlet head into the outlet pipe when it is still viscous-elastic. PTFE powder represents 20% by weight compared to the oil in which it is dispersed. The friction coefficient between the inner surface of such a tube and the protective sleeve made of HDPE (the same commercial name as above) is 0.075.

Under the same conditions, the PTFE powder interacts with silicone oil in such a way that it significantly reduces the friction coefficient from what is otherwise:

- no friction coefficient of 0.19 is achieved without treatment of the inner surface of the pipe;

- only the injection of silicone oil achieves a friction coefficient

0.102.

EXAMPLE 2:

The 8 mm thick cable is pushed in by blowing and molding it into a 2400 m long installation line made of high specific gravity polyethylene (HDPE), with an inside diameter of 26 mm and wall thickness

2.2 mm. In the first case, the inner surface of the installation line is coated with liquid lubricant (silicone oil) represented in the example.

1. In the second case, however, the inner surface is coated with a solid powdery lubricant equal to that in Example 1.

In the first case, it is not possible to install a cable longer than 400 m, while in the second case, it is possible to install a cable up to 700 m, subject to the same other conditions.

EXAMPLE 3:

The installation duct, made of high specific gravity polyethylene, has an inside diameter of 27 mm and a wall thickness of 3 mm. Used for installation of 17.6 mm outer diameter cable so that the inside surface of the installation line is first coated with silicone oil with a viscosity of 0.1 Pa s, second with a Teflon powder with a particle thickness of 10 pm and a third time with a powder mixture in the aforementioned oil with a weight ratio of 10% powder based on the oil used.

In these three cases, the measured friction coefficient was between pushing or plugging the cable into the installation line: first 0.102, second 0.071 and third 0.0061.

s EXAMPLE 4:

The installation duct is made of polyethylene of high specific gravity and has an inside diameter of 27 mm and a wall thickness of 3 mm for the installation of an external diameter cable of 17.6 mm. It is used in such a way that the inner surface of the io water coated with a lubricant mixture is composed of a liquid lubricant (silicone oil) with a viscosity of 0.1 Pa s, by increasing the weight ratio of the mixed solid lubricant (TEFLON® powder) each time with the same particle size, and otherwise consecutive: 5, 10, 15 and 20% with respect to the aforementioned oil.

is In these four cases, the measured friction coefficient during thrusting or. plugging the cable into the installation line: first 0.086, second 0.085, third 0.089 and fourth 0.090.

For:

NOVOPLASTIC

Claims (5)

PATENT APPLICATIONS 1. A tubular expansion product having the same cross-section along its entire longitudinal direction comprises a rigid tube (1) consisting of at least one type of plastic that is sufficiently flexible to be able to bend and unwind, as well as to be suitably rigid, to withstand centripetal and centrifugal forces, said solid tube having an inner layer and / or an outer surface (3) whose free surface forms a friction surface and said surface layer consists of a plastic form in which io is a dispersed lubricant marked with by interacting, on the one hand, particles (4) of a lubricant of a solid type disposed in plastic form, and these particles are at least partially dispersed in the free surface of the surface layer, and, on the other hand, a lubricant of a liquid type, is combined in a plastic form, and effectively dispersed in the surface layer without wetting its free surface. 2. Tubular product according to claim 1, characterized in that 20 that the lubricant is silicone. 3. Tubular product according to claim 1, characterized in that the liquid lubricant has a viscosity of not more than 1000 mm ² / S at room temperature and e.g. between 10 and 1000 mm ² / S. 4. Tubular product according to claim 1, 5, characterized in that the particles (4) of the solid lubricant are microscopically small with a diameter of not more than 20 pm, and preferably between 1 and 15 pm. 5. Tubular product according to claim 1, io characterized in that the solid tube (1) consists of at least a plastic form in which the particles (4) of the dry lubricant are arranged and these particles are dispersed in at least one, internal or external, free surface (2), thus forming a dry friction surface. 15 6. Tubular product according to claim 5, characterized in that the liquid lubricant is substantially liquid and dispersed in the plastic effectively and without wetting, or the outer or inner surface of the plastic form in question. 7. Tubular product according to claim 6, characterized in that the liquid lubricant contains an additive in a weight ratio to the plastic form of at least 0.02%, or preferably in the ratio of 0.02% to 0.08% by weight relative to the form in question. 5. The expansion tube according to claim 7, characterized in that the ratio of solid / liquid lubricant is at least 5%, preferably between 5 and 20%, and for example 10%.