摘要:
A method for producing extruded polyvinyl chloride (PVC) is disclosed. The method comprises supplying PVC powder and additives in a batch containing predetermined proportions to a high speed mixer (10), mixing and heating the batch in the mixer (10) to produce a PVC/additive blend, conveying the PVC/additive blend directly an extruder (16), and heating and extruding the PVC/additive blend in the extruder (16).
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.
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, 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:
An optical fibre cable (1) for installation in a duct by means of fluid flow is described. The cable (1) has a signal transmitting portion comprising a plurality of elongate, flexible optical fibres, surrounded by a braided covering (10) formed from textile yarns (9).
摘要:
A method is described of installing a lightweight (preferably less than 10 g/m) optical fibre unit into a tube by pulling using a pulling member. The pulling member may be attached to the pulling member by a braided sheath, or the pulling member itself be a braided tube.
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 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.
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 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.