Hydraulic and earth engineering – Subterranean or submarine pipe or cable laying – retrieving,... – With protection or indication of pipe or trench
Reexamination Certificate
1998-05-06
2002-04-16
Will, Thomas B. (Department: 3673)
Hydraulic and earth engineering
Subterranean or submarine pipe or cable laying, retrieving,...
With protection or indication of pipe or trench
C405S155000, C405S179000, C037S365000, C037S367000, C037S378000, C037S464000
Reexamination Certificate
active
06371691
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a process for introducing an optical cable, consisting of a tube and optical waveguides introduced therein, into solid ground with the aid of a laying unit.
BACKGROUND OF THE INVENTION
DE-A1-41 15 907 discloses a cable-laying plough for laying cables in the ground, in particular in the ground under water. In this case, the blade of the cable-laying plough has arranged in front of it a rotating cutting wheel which, in addition, is made to vibrate vertically, with the result that hard objects located in the region of the trench which is to be excavated may thus also be broken up thereby. This cable-laying plough excavates relatively wide trenches by displacing the soil with the aid of the plough blade. Such machines are used, in particular, in coastal areas and under water using corresponding control devices. For laying operations in the ground, the material is usually removed over a width of from 60 to 100 cm and a cable-laying depth of approximately 70 cm, with the result that the outlay for the laying operation is relatively high.
Furthermore, DE-A1-30 01 226 discloses a line network for transmitting signals, the signals being passed through fibre-optic cables which are laid in a network of pipes or ducts of an existing supply system. In this case, however, fixed cable-laying routes are predetermined, and inlets and outlets for the cable which is to be laid have to be provided in a suitable manner therein.
SUMMARY OF THE INVENTION
Alternatively to this, use may also be made, over short distances, of so-called drilling or jetting processes in which a tube is introduced horizontally into the ground. The high outlay for laying machines and material is also disadvantageous here.
JP-A-
6
1 107 306 discloses an optical waveguide which is provided with a metal tube in order to increase tensile strength. The optical waveguide is provided with a sheath of vinyl, nylon or urethane, these materials having elastic properties and thus protecting the optical waveguide mechanically against external influences. In order to increase the tensile strength, a metallic tube is also applied, loosely at first. Then the tubes are stretched and thus secured to the sheathed optical waveguide.
FR-A-2 677 137 discloses a repair method for optical cables which are composed of a tube and optical waveguides running therein. At the defective point, an adapted tubular element is inserted, to which the ends of the defective tube are connected again, the defective point being bypassed.
EP-A-0 553 1991-A discloses a repair method for conventional optical cables, two cable sleeves being used in which the connections are made between the optical waveguides by means of an intermediate cable element.
The object of the present invention is to provide a process for introducing an optical cable in which the outlay for the laying operation can be reduced, it also being intended that the outlay for the optical cable system used be coordinated with the laying method. The set object is achieved according to the invention, by a first process
of the type explained in the introduction, in that the optical cable used is a microcable or minicable having an external diameter of the tube of 2.0 to 10 mm, preferably 3.5 to 5.5 mm, the tube being homogeneous and pressurized-water-tight,
a laying channel with a width of 4.5 to 12 mm, preferably 7 mm, which is adapted to the diameter of the microcable or minicable, being introduced with the laying unit into the solid underlying laying surface,
the microcable or micro[sic]cable being introduced into the laying channel by means of a feed element and being held at a constant laying depth, the laying channel being filled with filling material using a filling device which is moved along after the insertion of the microcable or minicable.
The object which has been set is thus achieved in accordance with the invention planning to a second method of the type mentioned at the beginning in such a way that a microcable or minicable with an external diameter of the tube of 2.0 to 10 mm, preferably 3.5 to 5.5 mm is pressed into utility lines for sewerage, gas or water, which have been left open, using a laying unit.
The object which has been set is achieved according to the invention using a third method of the type mentioned at the beginning in that the optical cable used is a microcable or minicable with a diameter of the tube of 2.0 to 10 mm, preferably 3.5 to 5.5 mm, which is inserted into existing, active utility lines for sewerage gas or water using a laying unit.
A great advantage of the process according to the invention is that only a relatively short amount of time is taken for the laying operation, with the result that it is used particularly wherever long-term hold-ups are undesirable. This is the case, for example particularly when laying new or additional cables, when the laying operation has to be carried out in urban areas with heavy traffic. Blocking off or diverting is to be avoided as far as possible. The operations of cutting, laying and sealing the channel can take place directly one after the other, these operations expediently being carried out all in one go by a multipurpose machine. In this manner, the traffic disruption is barely greater than that caused by a road sweeper. There is also such a need, for example, when all the laid pipes, cable ducts or pipelines have already had cables laid in them, it then being possible to splice onto the newly laid cables without interruption. Tubular mini communication cables, which are referred to as microcables or minicables, are particularly suitable for this purpose. These newly laid minicables or microcables may preferably be connected to form a redundant overlay network.
According to the invention, such a minicable or microcable comprises a homogeneous and pressurized-water-tight tube of very small diameter of from 2.0 to 10 mm, preferably 2.2 to 5.5 mm. These tubes have a wall thickness of from 0.2 to 0.4 mm. The most favourable values as regards the buckling resistance are achieved with a wall thickness to an external diameter ratio of between 1/5 and 1/20, preferably approximately 1/10. The smallest internal diameter of the tube used is 1.8 mm. This tube may be produced from metal, for example from chromium-nickel-molybdenum (CrNiMo188) steel, aluminium alloys, copper or copper alloys or from plastic, for example with reinforcement inserts consisting of carbon fibres, glass fibres, or a sintered carbon-fibre structure. These tubes may be extruded, welded, folded or bonded longitudinally at the overlap. The optical waveguides are then introduced into the tube either after the empty tube has been laid or at the factory. The optical waveguides can be blown in or jetted in.
The tubular minicable can be introduced into solid ground by various types of process according to the invention:
1. The laying may be carried out by means of a laying machine which has a cutting wheel, with the aid of which a narrow laying channel having a width of from 4 to 12 mm, preferably 7 mm, and a depth of from 50 to 100 mm, preferably 70 mm, is cut in the ground, in particular in an existing roadway.
2. Such a minicable may also be forced into disused supply lines (wastewater, gas, water). Disused pipelines of utility companies are particularly suitable for a laying operation. They correspond largely with the supply network planning to be set up. Even if the disused pipes are in bad condition, it is possible to introduce the thin metal tubes of the minicable since they are pressed in in the longitudinal direction and pass through obstructions such as dirt, rust and the like. The minicable does not buckle in pipes since it is supported by the disused supply line. After leaving these pipelines, the laying operation may also be continued with the aid of other laying processes.
3. It is likewise possible for a minicable to be pushed into existing, active supply lines (wastewater, water). The function of the supply lines is barely impaired to any extent at all in this case. The tubular minicable i
Finzel Lothar
Kossat Rainer
Kunze Dieter
Zeidler Günter
Mayo Tara L.
Siemens Aktiengesellschaft
Will Thomas B.
LandOfFree
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