Pipes and tubular conduits – Repairing
Patent
1995-05-11
1998-01-27
Brinson, Patrick
Pipes and tubular conduits
Repairing
138 98, 138114, 72370, 264 36, F16L 5518, B21B 1702
Patent
active
057113513
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a method of forming an opening through the wall of a pipe, and also to a tool for forming such an opening. The invention further relates to a method of fitting a replacement fill-pipe into an existing fill-pipe of a tank, such as of an underground tank containing a flammable and volatile liquid--for example, petrol.
A common form of petrol tank comprises a steel (but sometimes reinforced plastic) vessel buried below ground level and having an upstanding neck provided on the top thereof, with an outwardly directed flange. The tank is closed by means of a lid Which fits over the neck opening and is bolted to the flange in a liquid and gas-tight manner. Pipes for filling and drawing liquid from the tank, along with other services such a level indicator, pass through the lid and are connected to appropriate pipework and so on within a chamber in the ground above the lid, which chamber is conventionally closed by a man-hole cover.
In one common kind of arrangement for such a tank, the lid is made of steel and has a circular opening therethrough in which is welded a steel sleeve having upper and lower internal threads. The fill-pipe itself may have external threads which are engaged with the lower threads of the sleeve, to project downwardly into the tank from the lid. Above the lid, appropriate pipe-work is provided to allow the filling of the tank, through the sleeve and fill-pipe.
In the case of a below-ground garage forecourt tank intended to hold petrol, the opening of the tank by removing the tank lid has to be performed with great caution and special measures have to be taken in order to avoid the risk of fire and explosion. Generally speaking, this may be performed only once appropriate notice has been given to the local government authority. The tank must be emptied of all petrol, and is then filled with water to displace all petrol fumes and vapours. The above-lid pipework and other services have to be disconnected from the lid, and then the ring of bolts around the lid may be removed. Once done, the lid may be lifted together with the fill-pipe projecting downwardly therefrom. After the lid has been re-fitted to the tank, the tank has to be subjected to a pressure test, in order to ensure that a perfect seal has been formed between the tank lid and the neck flange. Once tested, the pipework and services are re-made to the tank lid, and then the tank has to be completely drained of water, before it can be placed back in service. Moreover, the water will be contaminated and so has to be disposed of with considerable care. It will be appreciated that the above procedures take a most considerable time and may be performed only by skilled personnel; a tank typically is out of service for one to three days if the lid has to be removed, for any reason.
In order to minimise the likelihood of environmental pollution, many local government authorities are now insisting on underground tanks used for petrol or other noxious fluids to be provided with an automatic anti-over-fill valve, to close off the fill-pipe when the liquid in the tank reaches a predetermined level. To do this, a simple existing fill-pipe must be removed and replaced by another fill-pipe having an anti-over-fill valve assembly installed at an appropriate location along the length of that pipe.
In our earlier British Patent Publication No. 2,255,382, we have proposed a method for changing a fill-pipe without the need to remove a tank lid, but this method can be used only in an assembly where a fill-pipe is welded to an externally threaded nipple which is in turn inter-engaged with the threads of a sleeve welded to the tank lid. That method cannot however be used where the fill-pipe is threaded directly into the sleeve, as has been described above. In this case, it has been necessary to remove the tank lid, unscrew the existing fill-pipe from the sleeve in the lid, screw in the replacement pipe, and then replace the lid. For the reasons discussed above, this is a time-consuming and expensive procedure.
It has been recog
REFERENCES:
patent: 4052880 (1977-10-01), Cullinan et al.
patent: 4440339 (1984-04-01), Tamai et al.
patent: 4505017 (1985-03-01), Schukei
patent: 4547944 (1985-10-01), Hayden
patent: 4592391 (1986-06-01), Wentzell
patent: 4807675 (1989-02-01), Sharp
patent: 4844322 (1989-07-01), Flowers et al.
patent: 5267279 (1993-11-01), Saito et al.
LandOfFree
Forming openings in pipes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Forming openings in pipes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Forming openings in pipes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-335802