WO1998013641A1

WO1998013641A1 - Pipe connection system and method for effecting a pipe connection at an angle to the wall of a pipe

Info

Publication number: WO1998013641A1
Application number: PCT/NL1997/000533
Authority: WO
Inventors: Michel Van Den Molengraft
Original assignee: Nyloplast Europe B.V.
Priority date: 1996-09-24
Filing date: 1997-09-24
Publication date: 1998-04-02
Also published as: NL1004099C2

Abstract

In a connection system (1) a second pipe (3) having a pre-formed circumferential edge, which is provided with sealing means (7), is sealingly fixed in the opening formed in a first pipe (2), whereby the pre-formed circumferential edge butts against the inner wall of the first pipe. A pipe sleeve provided with a pre-formed end, which butts against the outer wall of the first pipe, is slid over the second pipe. A nut is screwed onto screw thread formed on the other end of the second pipe, whereby the nut presses together the two pre-formed ends, between which sealing means are present. In this manner a connection between two pipes can be effected quickly without using any further fittings.

Description

PIPE CONNECTION SYSTEM AND METHOD FOR EFFECTING A PIPE CONNECTION AT AN ANGLE TO THE WALL OF A PIPE

The present invention relates to a connection system comprising a first pipe, which is provided with an opening in its wall, and a second pipe, which is provided with a pre-formed end comprising sealing means, whose diameter is smaller than that of the first pipe.

The present invention furthermore relates to a method for effecting a connection between an opening in a first pipe and a correspondingly pre-formed end of a second pipe.

A connection system and a method of this kind, which are for example used in extending a pipe system, such as a (usually underground) sewage system, are generally known. When such a pipe system is being extended and a second pipe having a smaller diameter is connected to a first pipe of said system, the first pipe is in practice sawn through in two places after being excavated, after which a T-piece or another connecting piece extending at a selected angle is inserted. Preferably the connecting piece is provided with double socket tees at both ends of its straight portion, which are slid over the two sawn- hrough ends, thus effecting a connection and a seal . The end of the second pipe is slid over the remaining end of the connecting piece, and connected thereto to form a watertight seal. Then the excavated hole is filled up again.

One drawback of the known connection system is the fact that it is necessary to excavate the underground first pipe all round along a considerable part thereof, which requires a substantial amount of time and manpower and/or the use of relatively costly excavation machines. This is all the more true when the pipes to be exposed lie deep in the ground. Furthermore the use of the known connection system leads to a relatively large amount of waste material in the form of sawn-off, wasted parts of the first pipe, which are replaced by at least part of the connecting piece.

The object of the present invention is to provide a connection system and a method for effecting a high- quality pipe connection of sufficient mechanical strength which is less labourious and time-consuming.

In order to accomplish that objective the connection system according to the invention is characterized in that the shape of the opening in the first pipe is substantially elongated, in particular ovoid (egg- formed) or elliptical, and that the opening of the first pipe and the end of the second pipe are shaped in conformity to each other, such that the end of the second pipe can be manoeuvred through the opening in the first pipe from outside, after which the pre-formed end comprising the sealing means butts against the inner wall of the first pipe.

The method for effecting the connection is according to the invention characterized in that said end is inserted into said opening up to a position near the inner wall of the first pipe opposite the opening, after which the second pipe is tilted and rotated until the desired angular position is obtained, and that said second pipe is subsequently pulled out of the opening so far that sealing means present on the pre-formed end of the second pipe bear against the portion of the inner wall of said first pipe that surrounds said opening.

The advantages of invention are the following:

the lateral connection can be positioned at any desired angle in order to optimize the inflow and through-flow through the pipe connection;

only one watertight connection is made, namely between the end of the second pipe and the opening of the first pipe, whilst according to prior art two watertight connections must be effected on either side of the straight portion of the connecting piece;

- it is not necessary to excavate the first pipe present in the ground all round. In principle it suffices to excavate only that portion of the pipe to which the second pipe is to be connected;

- only one opening needs to be sawn out instead of having to completely saw through the pipe present in the ground twice, as is usual with the prior art ,-

- the only waste material is the material sawn out of the first pipe to form the opening, whilst according to prior art even a complete pipe portion was sawn out, which had to be replaced by the respective pipe portion of the connecting piece;

the connection that is formed provides a high- quality and mechanically strong and stable airtight and watertight seal against the inner side of the first pipe;

the dimensions, surface roughness and dimensional tolerances of the parts of the pipe connection system are not critical;

- the direction in which the saw cut extends at the location of the edge of the opening depends on the angle which the first and the second pipe include with each other;

the connection system according to the invention comprises few parts;

the opening weakens the pipe only minimally, and only in so far as this is necessary; and

all kinds of (light-weight) pipes or for example concrete pipes can be sealed.

The above advantages make the present invention, which can in principle be used for any angle, in particular for angles ranging from 30 - 60°, less costly, labourious and time-consuming.

The present invention will now be explained in more detail with reference to the accompanying drawings, wherein like numbers are numbered alike.

In the drawings

Figure 1 shows an embodiment of a connection system according to the invention, which can be fitted at an angle into an existing main pipe;

Figures 2 and 3 respectively show a threaded inlet and a pipe sleeve to be fitted round said threaded inlet and a nut to be used in the connection system of Figure 1 ;

Figure 4 is a view of the elongated opening in the already existing pipe of Figure 1 ;

Figures 5 - 9 show the successive positions which the threaded inlet and the pipe of Figure 1 occupy when a connection is being effected between the opening in the pipe and a correspondingly pre-formed end of the threaded inlet; and

Figure 10 shows the embodiment of Figure 1 provided with a mounting notch.

Figure 1 shows a. connection system 1 comprising a first pipe 2 and a second pipe or threaded inlet 3. Pipe 2 is provided with an elongated, usually ovoid or elliptical opening , which is shown in more detail in Figure 4. The opening is formed in pipe 2 by sawing, possibly with a hand-held saw. Pipe 3 is shown in Figure 2. This pipe or threaded inlet 3 comprises a pre-formed end 5 in the shape of an upright circumferential edge. Circumferential edge 5 is shaped in such a manner that when threaded inlet 3 is inserted in opening 4 of pipe 2, said circumferential edge 5 will just bear against the inner side 6 of pipe 2 near opening 4. Sealing means in the shape of a sealing ring shown in Figure 1 are provided on circumferential edge 5. The pre-formed end 5 of threaded inlet 3 is inserted into opening 4 in a manner yet to be explained. After making the connection between said end 5 and opening 4, a pipe sleeve 8, which is shown in more detail in Figure 3, is slid over threaded inlet 3. This leads to the situation shown in Figure 1. Pipe sleeve 8 is provided with a pre-formed end 9, which, as is shown in Figure 1, has been brought in mechanical contact with the outside 10 of pipe 2 surrounding opening 4. The other end 11 of threaded inlet 3 is provided with for example "blown" screw thread 12, onto which a nut 13 can be screwed. When nut 13, which functions as a pressure means, is tightened, sealing means 7 are pressed together between the respective ends 5 and 9 being moved together, as a result of which a connection, which is a watertight to a pressure of up to 1 bar, for example, is formed between pipes 2 and 3 and pipe 2 is also clamped down mechanically. Of course the angle a which the circumferential edge makes with the threaded inlet 3, which is diagrammatically illustrated for a given location on end 5 in Figure 2, depends on the place where said end 5 makes contact with the cylindrical inner side 6 of pipe 2. Angle not only depends on the radius of curvature of inner side 6 of pipe 2, but also on the angle which the longitudinal axes 14 and 15 of the respective pipes 2 and 3 include with each other. Although the present description of the drawing proceeds from an acute angle between the longitudinal axes 14 and 15 of about 45°, it is in principle possible to realise any desired angle between pipes 2 and 3 in the manner explained in the above. For use in practice angles ranging from 30 - 60° are perhaps of more importance.

Successive figures 5, 6, 7, 8 and 9 diagrammatically show the manner in which second pipe or threaded inlet 3 is inserted into opening 4 of first pipe 2. In Figure 5 the pre-formed end 5 will move towards opening 4 until the situation shown in Figure 6 is reached, wherein said end 5 is practically in contact with the inner side 6 opposite the opening 4 in pipe 2. Then pipe 3 is tilted and simultaneously rotated in the manner shown in Figure 7, until the situation shown in Figure 8 is reached, wherein further tilting of pipe 3 becomes possible and the situation shown in Figure 9 is reached after pipe 3 has been pulled out of opening 4 as far as possible. The various movements and rotations are indicated by means of arrows. Finally the situation which is shown in more detail in Figure 1 is reached.

In practice it has appeared to be advantageous to provide threaded inlet 3 with a local, usually annular or wedge-shaped protrusion 16 near end 5, which protrusion ensures that threaded inlet 3 is more or less locked in position in opening 4 when pipe sleeve 8 is slid over said threaded inlet, and will not move out of said opening. Said protrusion also prevents threaded inlet 3 from rotating as well. Threaded inlet 3 is furthermore provided with a stop shoulder 17.

If first pipe 2 is provided with an ovoid (seen in perpendicular projection) opening 4, as is to be preferred, and threaded inlet 3 is provided with a correspondingly shaped end having an upright edge or flange 5, the following advantage is obtained.

When the largest diameter B of the ovoid has been shifted in the direction of the end of threaded inlet 3, the widest portion B has been moved forward a distance V along the longitudinal axis of the threaded inlet in comparison to a situation wherein the widest portion B is located in the centre P of the opening (Figure 10) . Upon insertion of the threaded inlet, the widest portion of the flange will thus have passed the opening already halfway before the end has been inserted halfway into pipe 2 through opening 4 , as a result of which the rotation of the threaded inlet with respect to the pipe can be started sooner.

When the largest diameter B of the ovoid has been shifted in the direction of the end of threaded inlet 3, the widest portion B of the threaded inlet is also positioned closer to the side wall of threaded inlet 3 by a distance R, seen in radial direction, than in the situation in which the widest portion B is located in the centre P of the opening (Figure 10) . This makes it possible to insert a flange 5 having a larger dimension through opening 4 than in the situation wherein use is made of for example an elliptical (seen in perpendicular projection) opening 4 and a correspondingly shaped end comprising a flange 5. Figure 10 also shows a mounting notch M. The presence of said mounting notch M makes it easier to make the movements required for forming the connection (Figure 7) . This is important in particular for the unskilled user.

In practice it has furthermore become apparent that the connection with the ovoid provides a better seal. In addition to this it is even possible, when the ovoid is used, to connect a threaded inlet 3 to a pipe 2 whose diameter is practically the same as that of threaded inlet 3. This will be explained by means of the example below.

Pipes are manufactured in a number of preferred diameters, which increase in steps, for example 160 mm, 200 mm and 250 mm. Furthermore pipes are manufactured whose diameter increases in half steps, 180 mm and 225 mm.

A threaded inlet 3 having a diameter of 200 mm may for example be connected to a pipe 2 whose diameter is only a full step larger, that is, 250 mm. In that case the diameter of threaded inlet 3 is maximally 80% of the diameter of pipe 2. Preferably this ratio is maximally 72%, that is, a difference of one step and a half (for example a pipe diameter of 250 mm and a threaded inlet diameter of 180 mm) . More preferably the ratio is maximally 64%, that is, a difference of two steps (for example a pipe diameter of 250 mm and a threaded inlet diameter of 160 mm) .

When the ovoid is used, threaded inlet 3 need not be inserted through opening 4 in pipe 2 in a direction perpendicularly to the central axis of pipe 2, as is the case when a connection with an elliptical opening 4 is made, but it may for example be inserted through opening 4 at an acute angle. This has appeared to be important, in particular because it has become apparent in practice that it is not always possible to have said insertion through the opening take place substantially perpendicularly, this in connection with the available manoeuvring space .

It is noted that the term ovoid is understood to mean a two-dimensional projection of an egg, that is, a shape which is substantially symmetrical with respect to its longitudinal axis, and whose maximum transverse dimension is located at a place which is in particular shifted more than 15% of the length of the longitudinal axis with respect to the centre of said longitudinal axis .

Claims

1. A connection system comprising a first pipe, which is provided with an opening in its wall, and a second pipe, which is provided with a pre-formed end comprising sealing means, whose diameter is smaller than that of the first pipe, characterized in that the shape of the opening in the first pipe is substantially elongated, in particular ovoid or elliptical, and that the opening of the first pipe and the end of the second pipe are shaped in conformity to each other, such that the end of the second pipe can be manoeuvred through the opening in the first pipe from outside, after which the pre-formed end comprising the sealing means butts against the inner wall of the first pipe.

2. A connection system according to claim 1, characterized in that said pre-formed end includes an upright circumferential edge.

3. A connection system according to claim 2, characterized in that the angle a which the circumferential edge includes with the wall of the second pipe depends on the shape of the portion of the inner circumference of the first pipe where said portion butts against said inner wall, and on the angle at which said second pipe extends with respect to said first pipe.

4. A connection system according to any one of the claims 1 - 3, characterized in that a pipe sleeve provided with a pre-formed end is slide over said second pipe present in the opening of said first pipe, which pre-formed end of said pipe sleeve butts against the outer wall of said first pipe.

5. A connection system according to claim 4, characterized in that said pre-formed end of said pipe sleeve includes an upright circumferential edge .

6. A connection system according to claim 5, characterized in that the angle at which the circumferential edge of the pipe sleeve extends with respect to the wall of said pipe sleeve depends on the shape of the portion of the outer circumference of the first pipe where said portion butts against said outer wall, and on the angle at which said pipe sleeve extends with respect to said first pipe.

7. A connection system according to any one of the claims 4 - 6, characterized in that the connection system includes pressure means, which are in mechanical contact with said first pipe and with said pipe sleeve, which pressure means function to press said sealing means against the inner wall of said first pipe with the pre-formed end of said second pipe.

8. A connection system according to claim 7, characterized in that said second pipe is provided with screw thread, onto which the pressure means, which are provided with a nut, can be screwed.

9. A connection system according to any one of the claims 1 - 8, characterized in that the wall of said second pipe is provided with a stop shoulder.

10. A connection system according to any one of the claims 1 - 9, characterized in that a local protrusion is provided on the outside, near the pre-formed end of said second pipe.

11. A method for effecting a connection between an opening in a first pipe and a correspondingly preformed end of a second pipe, characterized in that said end is inserted into said opening up to a position near the inner wall of the first pipe opposite the opening, after which the second pipe is tilted and rotated until the desired angular position is obtained, and that said second pipe is subsequently pulled out of the opening so far that sealing means present on the pre-formed end of the second pipe bear against the portion of the inner wall of said first pipe that surrounds said opening.