IE61491B1 - A temporary or permanent blocking of the bore of a pipe - Google Patents

Description

The present invention relates to the temporary or permanent blocking of the bore of a pip® through which fluid flows and is particularly directed to the temporary blocking of a service pipe carrying natural gas.

The present invention is divided ©nt from Patent Specification No. 2157/88 and is related to Patent Specification No. _.

Should a gas supplying authority wish to cut off the supply of gas to a consumer for any reason (e.g. the consumer has defaulted on payment of a hill), safety regulations require that the gas supply be eventually cut off at a point outside the consumer's property or premises.

One method of achieving this is to dig down outside the property or premises to the service pipe connection to the main and then to cut the service pipe and plug it with a settable sealing compound t© cut off the supply.

In the case where the property comprises a block of flats the service pipe may be sealed by an expanding polyurethane foam.

The above method is inconvenient since it involves excavation to cut off the supply and it is therefore an object of the present invention to provide a method for cutting off a gas supply without this disadvantage.

According therefore to on,® aspect of the present invention we provide a method for temporarily or permanently blocking the bore of a pipe to the flow of fluid towards one end of the pipe using a seal which is adapted to form within the bore of the pipe a force fit sufficient both to resist any attempt to dislodge it by the pressure of the fluid and to prevent any fluid flowing past it t© the end of the pipe# the method comprising connecting the seal to a tether, insert ing the seal into the pipe end# causing the seal to move along the pipe counter to the direction of fluid flow until a predetermined length of tether is located within the pipe behind the seal indicating that the seal has reached a predetermined position within the pipe# the tether being released from the seal while the seal is still within the pipe and then withdrawn from the end of the pipe.

According ta another aspect of the present invention «β provide apparatus for temporarily or permanently blocking the bore of a pipe at a position upstream of a pipe end to which a fluid flows# the apparatus comprising a seal for insertion into the end of the pipe# a tether for connection to the seal# means for forcing the seal along the pipe counter to the direction of fluid flow until a predetermined length of tether is located within the pipe indicating that the seal has reached its predetermined position within the pipe, the seal being adapted to fora within the bore of the pipe a force fit sufficient both to resist any attempt to dislodge it fey the pressure ef the fluid and to prevent any fluid flowing past it to the end ©f the pipe, the tether being connectable to the seal in such a way that when the seal has reached its predetermined position within the pip® the tether aay be released fro» the seal while the seal is still within the pipe and then withdrawn from the end of the pipe.

An embodiment of the invention will new be particularly described, with reference to the drawings in which :Figure 1 is a schematic arrangement of a typical property connected to a natural gas supply, Figure 2 illustrates suitable equipment for effecting the aethod,,, and Figure 3 is a view partly in section of a suitable seal and associated cable and stop for limiting the distance travelled by the seal along the service pipe.

Referring to Figure 1, there is shown located within an outhouse or garage 1 adjacent to the dwelling 2 a gas meter 3 and a gas meter tap < which latter enables the consumer to turn off the gas supply. The gas is supplied to the meter 3 by means gi a service pipe 5 which is connected at its far end to a feeder main (not shown). To satisfy safety regulations, should it prove necessary for the gas supplying authority to cut off the consumer, the gas supply must be cut off at a point outside the outhouse 1 i.e. at a point is the service pipe which lies below ground.

In the case of the present invention, this is generally effected in the following manner.

Firstly, the gas aeter tap 4 is closed to shut off the gas supply to th® sefcer 3.» Sext the gas meter tap 4 is disconnected from the meter 3 and then a compressible seal is inserted into the now open outlet end of the gas tap 4,, the seal forming within the tap 4 and also within the bore of the service pipe 5 a force fit sufficient t© resist attempts by the gas pressure to dislodge it. The gas meter tap 4 is then opened and the seal is forced along the service pipe 5 te a suitable point beyond the outhouse e.g. to a point in the underground section of the service pipe 5.

As shown in Figure 3 th® seal may be in the form of a ball 6 of a resilient compressible material e.g. a resilient thermoplastic. The ball 6 say be forced along the service pipe S by pressurised gas e.g. natural gas. Tse'ball 6 itself is held on a flexible seal tether or cable 7. The latter has an externally threaded end 8 which is releasably screwed into an internally threaded bush 9 held captive within the ball 6. A movable stop 10 is threaded on the cable 7 to adjust the length of cable 7 following the ball 6 for the purpose to be described. The stop ie can be releasably secured to the cable 7 by means of a thuab-screv ll which engages the cable 7 as shown.

The ball 6 is noved by applied ga© pressure pushing a grease lubricant ahead of it until the step 10 engages with a predetermined limit means and the cable 7 becomes taught. The gras pressure behind the ball 6 'is then released and, the cable 7 unscrewed by twisting it to release its end S fro® the bush 9. The cable 7 can then fee removed, the gas tap 3 closed and the $ service pipe 5 sapped off, if necessary. The length c>£ cable 7 between the ball 6 and tbe step 10 can be adjusted to ensure that the ball 6 is outside the consumer’s dwelling» If it is intended permanently to block tbe bore of tbe pipe tbe ball may simply be left in position. In addition tbe pipe may be plugged with a suitable sealant at a point within the pipe between the bail and the pipe outlet.

If bowever, it is possible that tbe consumer may be reconnected at some time in the future the pipe is not plugged with sealant.

In order to reconnect the censwer to the gas supply the Ball 6 may be sucked out of the service pipe by means off a vacuum pump.

It may be necessary to spray the walls of tbe service pipe with lubricant to effect such removal.

The equipment shown in Figure 2 comprises a reception chamber 20 for the ball, having one end 21 for connection te the gas tap outlet 22 and an opposite end 23 comprising a gland (not shown) through which the cable 7 can be inserted, the gland is use forming a seal with the cable 7. Valves 24,25 on opposite sides of the chamber 20 provide means for connecting the chamber 20 t© a source of compressed natural gas where the ball is to fee forced up the pipe or to a vacuus pump -where the ball is to be removed from the pipe. The opposite end 23 of the chamber 2© has a nut 26 serving as a limit for movement of the cable stop lt„ } In use off the equipment to insert the ball 6 into the service pipe 5, the threaded end s off the cable 7 is inserted through the gland end off the chamber 20 and is then screwed into the threaded bush 9 off the ball 6. The ball € is then pulled by the cable 7 into the. chamber 2Cs. The chamber 20 is then connected to the gas tap outlet 22 (the tap at this stage being closed}) and the valve 24 say is connected to a supply off compressed natural gas (the valves 24,25 being closed). The gas tap 4 is opened and then the valve 24 is opened causing the ball 6 tc be forced along the service pipe 5 until the stop 10 engages with the nut 26. The stop 10 is the® released from the cable 7 and is slid away from the nut 26 to enable the cable 7 to be released from the ball 6. Any excess gas pressure in the pipe 5 is released by opening the other chamber valve 25. The gas tap 4 say the® be closed and the chamber 20 removed from the gas tap 4.

In order t© remove the ball 6 from the pipe 6, the chamber 20 is reconnected to the gas tap 4 and a vacuum pump is connected to the valve 24 say (both valves 24,25 being closed at this stage). The gas tap 4 is opened and then the valve 24 is opened t© cause the ball 6 to be sucked out from the service pipe 5 into the chamber 2®. The gas tap 4 is then closed and the chamber 20 removed from the gas tap 4The method described enables the consumer to be cut off at a point outside the consumer’s· premises without the need to excavate whether the cut off is temporary or permanent. Where the cut-off may be temporary, reconnection can be made quite simply fro© within the consumer’s premises once again obviating the need for excavation,»

Claims (13)

1. fiMZSS

1. A method for temporarily or permanently blocking the bore af a pipe to the flow of fluid towards one end of the pipe using a seal which is adapted to form within the bore of the pipe a force fit sufficient both to resist any attempt to dislodge it by the pressure of the fluid and to prevent any fluid flowing past it to the end of the pipe, the Method comprising connecting the seal to a tether, inserting the seal into the pipe ©nd, causing the seal to move along th© pip® counter to the direction of fluid flow until a predetermined length of tether is located within the pipe behind the seal indicating that the seal has reached a predetermined position within the pipe, th© tether being released fro® the seal while the seal is still within the pipe, and then withdrawn from the end of the pipe.

2. X method as claimed in claim 1 in which the tether has a step thereon which, in use, travels from a first position to a second position as the seal passes along the pipe, the stop preventing the seal from moving beyond its predetermined position by engaging at its second position with an obstruction inhibiting further movement of the stop and thereby preventing further movement of the seal and tether.

3. A method as claimed in claim 2 in which the position of the stop along th® tether is adjustable to adjust the distance ΙΟ -( between the stop and the seal.

4. A method as claimed in any of claims 1 to 3 in which the seal and the tether are connected together hy a releasable threaded connection.

5. 5. A method as claimed in any of the preceding claims in which the seal has an internally threaded bush and the tether has a correspondingly threaded end for engagement with the bush.

6. A method as claimed in any of the preceding claims in which 10 the seal is compressed radially by the wall of the pipe forming the bore.

7. A method as claimed in claim 6 in which the seal is a resilient ball having a diaaeter greater than that of the bore of the pipe. 15 $. A method as claimed in any of the preceding claims in which the pipe end terminates in a valve through which the seal is forced into the pipe.

8. 9. Apparatus for temporarily or permanently blocking the bore of a pipe at a position upstream of a pipe end to which a 20 fluid flows, the apparatus comprising a seal for insertion into the end of the pipe,· a tether for connection to the seal, means for forcing the seal along the pipe counter to the direction of fluid flow until a predetermined length of ίΐ tether is located within the pipe indicating that the seal has reached a predetermined position within the pipe, the seal being adapted t© form within the bore of the pipe a force fit sufficient both t© resist any attempt to 5 dislodge it by the pressure of the fluid and to prevent any fluid flowing past it to the end of the pipe, the tether being connectable to the seal in such a way that when the seal has reached its predetermined position within the pipe the tether may be released from the seal while the seal is

9. 10 still within the pipe and the tether is then withdrawn fro» the end of the pipe. 10. Apparatus as claimed in claim 9 in which a stop is provided for location on the tether, the stop, in use,, travelling from a first position to a second position as the seal and <15 tether travel along the pipe and means is provided at the second position to engage the stop and prevent further movement of the seal beyond its predetermined position.

10. 11. Apparatus as claimed in claim 10 in which the stop is movable along the tether to adjust the distance between the 20 stop and the seal.

11. 12. Apparatus as claimed in claim 10 ©r 11 ia which the seal and the tether are connectable together by a releasable threaded connection.

12. 13. Apparatus as claimed in claim 12 in which the seal has an 25 internally threaded bush and the tether has a correspondingly threaded end for engagement with the hush.

13. 14. 5 15. 16. 10 17. Apparatus as claimed in any of claims 9 to 13, in which the seal is adapted to be compressed radially by the wall of the pipe forming the bore. Apparatus as claimed in claim 14 in which the seal is a resilient ball having a diameter greater than the bore of the pipe. A method as claimed in claim 1, substantially as hereinbefore described with reference to the accompanying drawings. Apparatus as claimed in claim 9, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings .