GB2091430A - Apparatus for pressurising domestic connection pipes - Google Patents

Abstract

An apparatus for pressurising domestic connection pipes so that they may be tested for leaks, comprises an inflatable bladder (17) at the end of a pressure pipe (19) which may be inserted into the pipe, a tubular body 23 which is connectible at 24 to the domestic pipe to be tested and through which the pressure pipe 19 is axially displaceable to enable the bladder to be positioned in the domestic pipe prior to its inflation, a stuffing box 26, 28 in one end of the tubular body 23 which can be tightened once the pressure pipe has been adjusted to seal it to body 23, and a connection piece 29 secured to the tubular body and through which the domestic pipe connected to the end of body 24 may be pressurised. <IMAGE>

Description

SPECIFICATION Apparatus for pressurising domestic connection pipes The invention relates to an apparatus for pressurising domestic connection pipes which branch off from the pipe mains, laid underground in the street along the houses, of the mains networks for public gas supply, water supply, remote heat supply etc., and lead into the individual buildings.

Leakages can occur in the domestic connection pipes due to corrosion damage on the pipes, the ageing of seals on installed shut-off fittings, ageing or drying out of hemp-sealed threadings on connection boxes and the like and due to settlement of the building or earth movements. In the case of water pipes which are operated with relatively high pressures, as a rule leakages become visible on the earth surface after a short time. In the case of gas pipes which are operated with relatively low pressures, however leakages very often make themselves noticeable only after a lengthy time, for example due to a gas smell or the death of plants, and there is also the danger that gas escaping into the earth, creeping along the pipe and penetrating into the interior of the building can form an explosive air-gas mixture.

Frequently the medium escaping from the pipe at a defective point firstly flows through the ground along the pipe and makes itself noticeable only at a more or less remote position, so that in the case of a leakage of the main pipe the impression can be given of a defective domestic connection pipe, and vice versa.

Both for the location of leakages and for the testing of domestic connection pipes which appear satisfactory, especially for the routine testing of domestic gas connection pipes, there is a need to be able to test the domestic connection pipes for tightness by a pressure test. This hitherto involved considerable difficulties however since while the domestic connection pipe is freely accessible in the interior of the house and therefore can be separated quickly and without trouble from the domestic pipe leading further into the building and can be closed, at the other end of the domestic connection pipe it is necessary, with high expenditure of labour and costs, to block the road in front of the house, tear open the surface of the road and excavate a trench, in order to be able to separate the domestic connection pipe from the pipe main and close it, after the pressure test the domestic connection pipe must again be connected to the main, the trench must be filled and the road surface repaired.

The invention is based upon the problem of avoiding the above-stated disadvantages and producing an apparatus which renders it possible, with the simplest conceivable means and minimum expenditure of labour and costs, to pressurise domestic connection pipes without the need of separating the domestic connection pipe from the pipe main with the consequently necessary trench in the street, for this purpose.

The solution in accordance with the invention to this problem is effected by the apparatus as characterised in Claim 1. This apparatus, its manner of operation and use and further inventive features will be described below with reference tc the example of a domestic gas connection pipe shown in diagrammatic representation in the drawings, wherein: Figure 1 shows a gas main pipe with a domestic connection pipe, Figure 2 shows a detail of Figure 1 with a part of the introduced apparatus according to Figure 3, Figure 3 shows the apparatus according to the invention in elevation, Figure 4 shows a section along the line IV--IV in Figure 3.

In Figure 1 a pipe drilling box 2 is secured with a gasket 5 by means of U-bolts 3 and nuts 4 on the gas main pipe 1. The main pipe 1, drilled through the drilling box 2, possesses an opening 6 the circumference of which is sealed by the gasket 5. Into the drilling box 2 there is screwed a pipe nipple 7 on to which a T-piece 8 with a screwed-in stopper 9 is screwed, and a domestic connection pipe 10 is connected to the T-piece 8.

The connection of the domestic connection pipe 10 to the main pipe 1 can also take place otherwise, for example by a threaded socket welded on to the main pipe 1. The domestic connection pipe 10, conducted through the masonry 11 of the building, is as a rule provided at its end in the house interior 12 with a clearing Tpiece 1 3 with a stopper 14 to which there are connected a main stop cock 1 5 and the domestic pipe 1 6 leading further into the building by way of a gas meter.

The apparatus as illustrated in Figures 3 and 4 possesses an inflatable cylindrical bladder 17, preferably of rubber, with a connection piece 1 8 and a pressure conduit 19 connected thereto, preferably a flexible hose. The diameter of the bladder 1 7 is dimensioned so that after the stopper 14 has been unscrewed from the clearing T-piece 13 (Figure 1) the bladder 17 can be introduced in the uninflated condition with the pressure pipe 1 9 from the interior 12 of the house into the opened domestic connection pipe 10 (Figure 2).At the other end of the pressure pipe 1 9 a pressure reducer or reduction valve 20 is arranged with a manometer 21 and a connection 22 for a pressure source, for example a compressed air cylinder, a compressor or the like.

The pressure pipe 1 9 is conducted axially displaceably through a tubular body 23 and can be sealed off in the latter (Figure 3). The tubular body 23 has at its forward end a connection 24 which is tightly connectable with the opened domestic connection pipe 10. In the example of embodiment as illustrated the connection 24 consists of a reduction piece which can be screwed into the clearing T-piece in place of the stopper 14. According to how the end of the domestic connection pipe 10 in the house interior 12 is formed, the connection 24 can be formed by an internal threading or external threading on the tubular body 23 itself, by a screw connection or another suitable adaptor piece.

The tubular body 23 also comprises a further connection 29 which is connectable through a pressure reducer or a reduction valve 30 with a manometer 31, a shut-off element 32 and a connection coupling 33, with a pressure-medium source, for example a compressed-air cylinder, a compressor, a pump or the like. The connection 29 will advantageously be formed by a lateral tubular connection piece 29 of the tubular body 23.

The connection 29 opens into the space 34 formed between the tubular body 23 and the pressure pipe 1 9 (Figures 3 and 4), which space is open at the forward end of the tubular body 23 and opens into the domestic connection pipe 10.

Towards the rear end of the tubular body 23 the space 34 can be closed in sealed manner.

In further development of the invention in the tubular body 23 a stuffing box is arranged which consists of a bush 25, soldered into the tubular body 23, as stuffing box seating, a socket 26 screwed on to the tubular body 23 as stuffing box housing, a rubber stopper 27, inserted into the socket 26 and abutting on the bush 25 as stuffing box packing, and of a screw ring 28. The bush 25, rubber stopper 27 and screw ring 28 posses a bore of such width that the pressure pipe 1 9 is axially displaceable when the stuffing box is not tightened. By tightening of the screw ring 28 the rubber stopper 27 is compressed and pressed firmly on to the pressure pipe 19 so that it tightly encloses the latter.At the same time the rubber stopper 27 is pressed against the bush 25 and the socket 26 so that the stuffing box at the same time also tightly seals off the space 34 towards the rear end of the tubular body 23.

For the purpose of pressurising the domestic connection pipe 10 the latter is opened in the interior 1 2 of the building, for example by removal of the stopper 14, and separated from the domestic pipe 1 6, for example by closing of the main stop cock 1 5. The tubular body 23 is tightly connected with its connection 24 to the opened domestic connection pipe 10, the bladder 17 with the pressure pipe 1 9 being at the same time introduced from the house interior 12 into the opened domestic connection pipe 10, in fact preferably initially so far that it finds abutment on the other end of the domestic connection pipe 10, this abutment being formed in the example of embodiment as illustrated by the wall of the Tpiece 8 lying in axial extension of the domestic connection pipe 10.Then the bladder 1 7 is retracted again into the domestic connection pipe 10 so that it reliably lies with its full length in the pipe of the domestic connection pipe 10. The bladder 1 7 is now inflated through the pressure pipe 1 9. The length of the cylindrical bladder, preferably provided with sealing rings of rib form on its circumference, and the pressure which can be set on the pressure reducer 20 and monitored on the manometer 21 are so selected that the pressure acting upon the bladder 1 7 in the axial direction during the pressure test is not capable of shifting the bladder in the pipe 10, but the domestic connection pipe 10 is closed in absolutely sealed and pressure-proof manner in the region of its entry into the main pipe 1, by the bladder 1 7. At the same time by tightening of the screw ring 28 the domestic connection pipe 10 is also tightly closed at its other end in the interior 12 of the house in the above-described manner.

Now by opening of the shut-off element 32 a pressure which can set on the pressure reducer 30 and monitored on the manometer 31 is conducted through the connection 29 and the space 34 into the domestic connection pipe 10 and then the shut-off element 32 is closed again. If during the following time of the pressure test the pressure on the manometer 31 does not remain constant, but the pressure in the domestic connection pipe 10 drops, then the latter has a leakage.

In this way with the apparatus according to the invention testing of domestic connection pipes by a pressure test is possible as simply and quickly as conceivable and with a minimum of expenditure of labour and costs.

Claims (4)

1. An apparatus for pressuring domestic connection pipes, comprising an inflatable bladder, introducible from the house interior into the opened domestic connection pipe, a pressure pipe connected to the bladder, a tubular body through which the pressure pipe is guided to be axially displaceable and which can be sealed off .around the pressure pipe, a connection in the tubular body which is connectable with a pressure-medium source and which communicates with a space formed between the tubular body and the pressure pipe.

2. An apparatus as claimed in claim 1 , further comprising a stuffing box arranged in the tubular body and in which the pressure pipe is axially displaceable, the stuffing box being capable of tightly enclosing the pressure pipe and being capable of tightly closing said space adjacent the end of the tubular body remote from the domestic connection pipe.

3. An apparatus as claimed in either claim 1 or claim 2, wherein the tubular body is provided with a lateral connection piece for the pressure-medium source opening into said space.

4. An apparatus for pressuring domestic connection pipes substantially as described herein with reference to the accompanying drawings.