Method for connecting a branch pipe to a main pipeline and underground network for distributing fluid
Method in which the following operations are carried out: a) digging an exploration hole ( 8 ) in order to open up a main pipeline ( 2 ) which has an upper edge ( 10 ) which extends at an upper level ( 12 ) which is substantially constant relative to the ground ( 6 ), b) using a branch connection ( 14 ) which has a support surface ( 16 ) and a shaft ( 18 ) to which the branch pipe is connected, c) positioning the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ) so that the shaft ( 18 ) is below the upper level ( 12 ) of the main pipeline ( 2 ), d) fixing the branch connection ( 14 ) to the main pipeline ( 2 ), e) placing the branch pipe and the main pipeline ( 2 ) in communication, f) refilling the exploration hole ( 8 ), whilst keeping the branch pipe below the upper level ( 12 ) of the main pipeline ( 2 ).
1. Method for connecting a branch pipe ( 4 ) to a main pipeline ( 2 ), in which the following operations are carried out:
a) digging an exploration hole ( 8 ) from the ground ( 6 ) in order to open up a portion of the main pipeline ( 2 ) which has an upper edge ( 10 ) which extends at an upper level ( 12 ) which is substantially constant relative to the ground ( 6 ),
b) using a branch connection ( 14 ) which has a support surface ( 16 ) in the form of a cylindrical portion and a shaft ( 18 ) which extends substantially perpendicularly relative to the support surface ( 16 ) and which is provided with a branch ( 20 ) which is substantially perpendicular relative to the shaft ( 18 ) and to which the branch pipe ( 4 ) is connected,
c) positioning the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ),
d) fixing the branch connection ( 14 ) to the main pipeline ( 2 ),
e) placing the branch pipe ( 4 ) and the main pipeline ( 2 ) in communication,
f) refilling the exploration hole ( 8 ),
characterised in that, during step c), the shaft ( 18 ) of the branch connection ( 14 ) is positioned, with the branch ( 20 ) thereof, entirely below said upper level ( 12 ) of the main pipeline ( 2 ), or substantially at the upper level ( 12 ) of the main pipeline ( 2 ) relative to the ground ( 6 ), and, during step f), the branch pipe ( 4 ) is kept below the upper level ( 12 ) of the main pipeline ( 2 ), or substantially at the upper level ( 12 ) of the main pipeline ( 2 ) relative to the ground ( 6 ).
2. Method according to claim 1 , characterised in that:
during step b), the branch pipe ( 4 ) is connected to the branch ( 20 ), and
during step c), the branch ( 20 ) is positioned substantially parallel with the main pipeline ( 2 ).
3. Method according to claim 1 characterised in that:
a positioning device ( 1 ) is used which comprises a support ( 36 ), means ( 34 ) for fixing the branch connection ( 14 ) to the support ( 36 ) and means for pressing the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ),
during step c), the support ( 36 ) is positioned from the ground ( 6 ) and
during step d), the means for pressing the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ) are operated from the ground ( 6 ).
4. Portion of an underground network ( 50 ) for distributing fluid, such as gas or water, said network portion comprising:
at least one main pipeline ( 2 ), said main pipeline ( 2 ) having an upper edge ( 10 ) which extends at an upper level ( 12 ) which is substantially constant below the ground ( 6 ),
a plurality of branch connections ( 14 , 14 ′) which are fixed to the main pipeline ( 2 ) and which each comprise a shaft ( 18 , 18 ′) which extends substantially perpendicularly relative to the main pipeline,
a plurality of branch pipes ( 4 , 4 ′) which extend in the ground ( 6 ), each branch pipe ( 4 , 4 ′) being connected to the main pipeline ( 2 ) by means of one of the branch connections ( 14 , 14 ′), for the circulation of fluid,
said network portion being characterised in that the shaft ( 18 , 18 ′) of each of the branch connections ( 14 , 14 ′) and each of the branch pipes ( 4 , 4 ′) are located entirely below said upper level ( 12 ) of the main pipeline ( 2 ), or substantially at the upper level ( 12 ) of the main pipeline ( 2 ) relative to the ground ( 6 ).
5. Network portion according to claim 4 , characterised in that the upper level ( 12 ) of the main pipeline ( 2 ) extends at a distance (d) from the ground ( 6 ) of between 40 centimeters and 50 centimeters.
6. Network portion according to claim 4 , characterised in that the main pipeline ( 2 ) extends along an extension axis and the branch pipes ( 4 , 4 ′) extend substantially parallel with the extension axis of the main pipeline ( 2 ) near the branch connection ( 14 , 14 ′).
7. Network portion according to claim 5 , characterised in that the main pipeline ( 2 ) extends along an extension axis and the branch pipes ( 4 , 4 ′) extend substantially parallel with the extension axis of the main pipeline ( 2 ) near the branch connection ( 14 , 14 ′).
8. Method according to claim 2 , characterised in that:
a positioning device ( 1 ) is used which comprises a support ( 36 ), means ( 34 ) for fixing the branch connection ( 14 ) to the support ( 36 ) and means for pressing the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ),
during step c), the support ( 36 ) is positioned from the ground ( 6 ) and
during step d), the means for pressing the support surface ( 16 ) of the branch connection ( 14 ) against the main pipeline ( 2 ) are operated from the ground ( 6 ).