Pipe joints or couplings – End to side or plate – Saddle-type clamp
Reexamination Certificate
1999-05-26
2001-05-01
Nicholson, Eric K. (Department: 3627)
Pipe joints or couplings
End to side or plate
Saddle-type clamp
C285S197000, C285S114000
Reexamination Certificate
active
06224116
ABSTRACT:
The present invention relates to a device for holding a secondary pipe in position on a branch connector which is to be mounted on a buried main pipe for transporting a fluid (natural gas, for example), and to a process for fitting a secondary pipe to a main pipe using that device, in particular from the top part of an excavation pit.
It is often necessary to install branch connectors on already existing underground pipes, such as gas or water distribution pipes, for example in order to connect consumers to a distribution system.
To that end, an excavation pit of restricted dimensions (in order, especially, to limit disruption to the movement of pedestrians or vehicles) may be produced, which does not allow a person to descend to the bottom of the pit, so that the operations of fitting the connector must be carried out from the top part of the pit (or “outside the pit”).
When the pipe and the branch connector are made of heat-meltable material, such as polyethylene, the branch connector is most frequently fixed to the pipe by welding. The body of the branch connector, which generally has the shape of a saddle (upper and, where appropriate, lower), is then equipped with an electrical resistor connected to two supply contacts for connection to a power supply in order to carry out the welding operation by melting the sole of the connector and welding it to the pipe. It is also necessary to introduce the secondary pipe (the diameter of which is generally slightly smaller than that of the main pipe) into a cylindrical sleeve with which the branch connector is equipped and which is arranged laterally with respect to its shaft, generally at a right angle to the main pipe. The sleeve is likewise provided with power supply contacts for the welding of the secondary pipe to the branch connector.
In order correctly to weld together the branch connector and the main pipe on the one hand and the secondary pipe and the branch connector on the other hand, apparatuses are already known which allow the secondary pipe to be positioned and held in place on the main pipe. Those apparatuses rest both on the main pipe and on the secondary pipe, most frequently with the aid of adjustable arms. To that end they generally use grips (or jaws) and/or pincer devices, most frequently with a variable opening allowing them to be adapted to different pipe diameters, which are placed on the said pipes.
However, those apparatuses are relatively complex and fairly expensive. Moreover, they are often bulky and heavy and hence not very practical to manipulate, especially from the top part of a pit having a small cross-section. Their main disadvantage is that they must be fixed both to the main pipe and to the secondary pipe. Finally, another disadvantage of that type of apparatus is that it is impossible to weld the secondary pipe to the branch connector from the top part of the pit because the main pipe, on which the apparatus is supposed to rest, is not accessible. Consequently, it is necessary to lower to the bottom of the pit the branch connector mounted on the pipe by way of the sleeve, with the risk that the said connector will rotate about the pipe or even become detached therefrom.
The object of the invention is, therefore, to remedy the above-mentioned disadvantages and to allow a secondary pipe to be fitted to a main pipe from the top part of an excavation pit of reduced size (cross-section), at low cost, without a specialised apparatus being immobilised for the entire welding and cooling time of the members. Another aim of the invention is to allow a branch connector to be fitted with the aid of equipment that is lightweight, of simple construction, compact and easy to use. The gas supply company is, therefore, able to use this invention more systematically in this type of intervention.
To that end, the invention consists of a device for positioning and holding together a secondary pipe and a branch connector before the said branch connector is mounted on a buried main pipe for transporting fluid, characterised in that the device rests solely on the secondary pipe and on the branch connector, away from the main pipe.
Accordingly, there is no danger that the branch connector and the secondary pipe will become separated. It is also possible to use the device of the present invention for welding the secondary pipe to the branch connector from outside the excavation pit (which was impossible with the devices of the prior art) since the two members are perfectly positioned and immobilised relative to each other by means of the said device.
In order that the branch connector and the secondary pipe are held correctly, the device will preferably rest on a vertical cylindrical shaft of the branch connector and on a portion of the secondary pipe after the latter has been introduced into a lateral sleeve of the branch connector.
According to an additional aspect, the said device will preferably comprise two arms which are at a distance from and parallel to each other, the said arms being joined by a curved end portion, which is able to be mounted around the shaft of the branch connector, and each terminating, at their free end, in a half-shell which is able to surround the secondary pipe.
In order to allow the device to be adapted to different secondary pipe diameters, each half-shell will preferably form a V surrounding the secondary pipe.
In order that the device is held on the secondary pipe correctly, it will be possible to surround the two half-shells with a securing collar.
Still with the same aim and according to an alternative embodiment, the two half-shells may have a substantially semi-circular cross-section and overlap partially in order to form a self-tightening serrated collar.
In order to allow the secondary pipe to be welded to the sleeve of the branch connector, the device will preferably have an opening between its arms allowing access to power supply contacts which are arranged on the sleeve of the branch connector and are intended for the welding of the said sleeve to the secondary pipe.
According to another aspect, the device will preferably be made of rigid plastics material and will be elastically deformable at least at its curved end. Accordingly, it will be possible to move the arms apart easily in order to position the device around the shaft of the branch connector before the half-shells of each arm are placed around the secondary pipe, that operation being facilitated by the “return” elasticity of the curved end portion of the device.
The invention relates also to a process for fitting a secondary pipe to a main pipe by way of a branch connector equipped with a vertical cylindrical shaft and a lateral sleeve, the said process comprising the following steps:
producing an excavation pit of a size that is smaller than that allowing a man to descend into it, and freeing at least the upper circumference of the section of the main pipe on which the branch connector must be fitted,
introducing, from the top part of the excavation pit, the secondary pipe into the sleeve of the branch connector,
holding the secondary pipe inside the said sleeve by means of the holding device described above,
lowering the assembly formed by the branch connector, the secondary pipe and the said holding device to the bottom of the excavation pit,
positioning the branch connector on the section of the main pipe,
carrying out the operations of welding the branch connector to the main pipe,
drilling a hole in the main pipe at the location of the shaft of the branch connector and closing off the shaft,
filling in the excavation pit again and leaving the device buried.
The operation of welding the sleeve to the secondary pipe may be carried out either before the assembly is lowered to the bottom of the excavation pit (that is to say, from outside the pit) or once the assembly has been lowered to the bottom of the pit, for example at the same time as the operation of welding the said branch connector to the main pipe.
In the case of the first solution, the operator manipulating the tools from the top part of the pit will
Caraveo Philippe
Le Cointe Patrick
Taillade Michel
Gaz De France (G. D. F.) Service National
Nicholson Eric K.
Rothwell Figg Ernst & Manbeck
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