摘要:
A tube assembly (1) comprises a dummy tube (2) formed from extruded medium density polyethylene and five primary tubes (3), also formed from extruded medium density polyethylene, and placed around the dummy tube (2). The primary tubes (3) are also provided with a co-extruded lining (not shown) on the internal surface thereof to minimise static attraction and friction between the tubes (3) and optical fibre units (not shown) subsequently installed into the tubes (3). The tubes (2, 3) and a rip cord (4), for subsequently removing the covering layers of the assembly to gain access to the tubes (2, 3), are surrounded by an outer sheath (5) formed from extruded medium density polyethylene. The outer sheath (5) is provided with a non-metallic water barrier (6), and is surrounded by a lubricant polymer layer (7) containing a polyethylene based lubricant compound, the active constituent of the lubricant being an organic silicone slip agent.
摘要:
A fibre optic cable (1) includes a core of primary coated optical fibres (2) embedded in an inner layer (3) of acrylate material, having sufficient tensile strength when cured to lock at least the outermost fibres (2) in place and still allow the fibres to be easily broken out of the assembly for termination and splicing purposes. The hardness of the acrylate layer (3) is such that at least the outermost fibres (2) of the bundle are restricted from moving axially relative to the inner layer 3. The inner layer (3) is then surrounded by a loose thin jacket (4) formed from a mixture of high density polyethylene having a Shore hardness greater than or equal to 60 and a generally uniformly distributed slip agent. The mixture from which the outer layer (4) is formed is compacted by means of heat and pressure.
摘要:
A fibre optic cable 1 includes a core of primary coated optical fibres 2 embedded in an inner layer 3 of acrylate material, having sufficient tensile strength when cured to lock at least the outermost fibres 2 in place and still allow the fibres to be easily broken out of the assembly for termination and splicing purposes. The hardness of the acrylate layer 3 is such that at least the outermost fibres 2 of the bundle are restricted from moving axially relative to the inner layer 3. The inner layer 3 is then surrounded by a loose thin jacket 4 formed from a mixture of high density polyethylene having a Shore hardness greater than or equal to 60 and a generally uniformly distributed slip agent, including a polyether modified poly (dimethylsiloxane) material such as polyether modified hydroxy functional poly (dimethylsiloxane) material. The mixture from which the outer layer 4 is formed is compacted by means of heat and pressure. The outer layer 4 may also contain a mineral filler, such as calcium carbonate and/or titanium dioxide, in order to improve the stability of the dimensions of the outer layer 4 as the temperature changes.
摘要:
A retaining device (52) for retaining a plurality of tubes (54) adapted to receive optical fibre cables is disclosed. The retaining device (52) has a support (58) that joins together several clips (56). Each clip (56) resiliently receives a tube (54) or bundle of tubes (54) and releasably retain the tube or bundle of tubes. The retaining device (52) is injection moulded and in use several retaining device (52) are spread equidistantly along the length of several tubes (54) to form a tube assembly.
摘要:
A fibre optic cable 1 includes a core of primary coated optical fibres 2 embedded in an inner layer 3 of acrylate material, having sufficient tensile strength when cured to lock at least the outermost fibres 2 in place and still allow the fibres to be easily broken out of the assembly for termination and splicing purposes. The hardness of the acrylate layer 3 is such that at least the outermost fibres 2 of the bundle are restricted from moving axially relative to the inner layer 3. The inner layer 3 is then surrounded by a loose thin jacket 4 formed from a mixture of high density polyethylene having a Shore hardness greater than or equal to 60 and a generally uniformly distributed slip agent, including a polyether modified poly (dimethylsiloxane) material such as polyether modified hydroxy functional poly (dimethylsiloxane) material. The mixture from which the outer layer 4 is formed is compacted by means of heat and pressure. The outer layer 4 may also contain a mineral filler, such as calcium carbonate and/or titanium dioxide, in order to improve the stability of the dimensions of the outer layer 4 as the temperature changes.
摘要:
A method of manufacturing a tube (8) is disclosed. The method comprises forming a tube (8) by extrusion, causing a body (24) to move longitudinally relative to the internal bore of the tube (8), and determining whether the body (24) ceases to move relative to the tube (8) At least part of said extrusion step and said step of causing a body (24) to move relative to the internal bore of the tube (8) are carried out simultaneously, and the body (24) is caused to move relative to the internal bore of the tube (8) by means of at least one first tensile element (22) attached to said body (24).
摘要:
A cable (302) has (8) fibres (304) are encapsulated by a UV curable layer (306) having a diameter of approximately (1010) microns, and (16) outer fibres (316) arranged in a circular formation around the inner fibres (304). The optical fibres (304) are held in position by means of the UV curable layer (306) so that the UV curable material of the layer (306) does not penetrate into the gaps between the optical fibres (304) and the outermost optical fibres (304) are restrained by the layer from moving axially. It is found that such an arrangement provides surprisingly favourable bending properties, making the cable particularly suitable for installation in a tube by means of blowing.