Connection sleeve for use with pipes and wells The present invention relates to a drill sleeve, in the following referred to as"a sleeve" for connection on pipes and wells. The product is especially suitable for application, if one wishes to make a branch pipe in pipes and wells of double walled construction, hereunder especially pipes and wells made from plastic. The branch pipe or the inlet is preferably made from rubber or plastic.

When an inlet or a branch pipe from a main is to be mounted, this is usually performed by cutting circular hole in the surface of the pipe. Pipelines and wells of this type which are included in the present invention typically have a round or oval cross sec- tion. At the place where an inlet or branch pipe is desired, a hole is drilled in the pipe- line with a round drill. Hereafter, a sleeve is mounted either around or in the hole it- self, thereby making a connection for the subsequent mounting and fastening of an inlet or the like to the main.

The hole drilled in the pipeline or the well has a diameter corresponding to an outer diameter of the sleeve, whereby the sleeve when mounted in the main pipeline, has an inner diameter corresponding to the pipe diameter, he wishes to apply in the inlet or in the branch pipe. Standard pipes are typically applied, i. e. pipes which can be ordered with fixed diameters with intervals depending on the user's wishes. Normally these are stocked commodities. The sleeves according to the invention are possibly made as stocked commodities in sizes that suit the pipes one could expect the user to apply for inlets and branch pipes.

The hole in the pipeline or well where one wishes the branch pipe or inlet to be ar- ranged is typically provided in that a circular drill that has a diameter corresponding to the outside diameter of the sleeve is applied in the adjustment zone of the sleeve.

When the drill is applied perpendicular to the pipe's longitudinal axis, a slightly oval hole is obtained. When the sleeve therefore is mounted in the hole, it will either be too small in one direction or too large in the other, depending on the size of the diameter chosen for the drilling of the hole.

Therefore, it is the object of the present invention to provide a sleeve that compensates for the slightly oval shape in the connecting hole in the pipe.

In the present description it is understood that the sleeve is suitable for mounting in all cylindrical items, hereunder especially pipes and wells.

This is performed, according to the invention, with a sleeve which is distinct in that the outside of the sleeve includes a first cylindrical part with an outside diameter cor- responding to the hole in the item with which the connection is to be made, a conical part continuous with the first cylindrical part and with a smallest outside diameter cor- responding to the diameter of the first cylindrical part, and a second cylindrical part with a diameter larger than the largest diameter of the conical part.

Mounting of a sleeve, according to the invention, typically includes the following steps: a) A hole with a diameter corresponding to the diameter of a first cylindrical part of the sleeve is drilled in the pipe where the inlet is wanted; b) the sleeve is arranged in the hole, such that a second cylindrical part, with a diame- ter larger then the first part, surrounds the hole on the inside of the pipe, that a conical part of the sleeve, provided between the first and second cylindrical part, is arranged in the hole, and that the conical part has an extension in the longitudinal axis of the sleeve corresponding to the pipe's wall thickness, that the conical part has a minimum diameter corresponding to the diameter of the first cylindrical part and arranged con- tinuous with the first cylindrical part, that a third cylindrical part arranged at the oppo- site end of the sleeve in the second cylindrical part and with a diameter larger than the diameter of the first cylindrical part, are arranged to overlap at least part of the outer side of the pipe; c) that the inside of the sleeve is possibly oiled with a suitable lubricant; d) that a delivery pipe is arranged inside the sleeve.

By designing the sleeve with a conical part arranged to be adjusted to the pipe's wall thickness, the pipe joint will during mounting adjust 100% to the slight oval shape, whereby a waterproof connection is obtained. At certain places in the circumference,

the conical part will only reach slightly into the wall thickness while at other places in the circumference, i. e. where the oval shape has arisen as a function of the circular hole being drilled in a round or oval pipe, the conical part will enter further into the wall thickness. Since the sleeve is also made from a relatively flexible material such as rubber or thermoplastic, the sleeve will be able to adjust to the geometry of the hole by itself. This will be strengthened further when the delivery pipe is placed in the sleeve.

The second cylindrical part with a diameter larger than the largest diameter in the conical part will form some kind of lip. It is the lip part's function to rest against the inside of the pipe, such that a passage between the pipe and the inlet is made. Thus, the lip is designed to surround the entire circumference of the hole on the inside of the pipe with a small overlap. Similarly, in a further embodiment of the invention a corre- sponding lip part can be arranged at the opposite end, arranged to surround part of the outer circumference of the hole.

The sleeve's extension in its longitudinal axis, i. e. an axis perpendicular to the pipe or well where the sleeve is to be inserted in, can be made such that it fits the thickness of the pipe. As a regular commodity, there are a number of double walled pipes or pipes with corrugating outsides of largely standard dimensions. The sleeve is made such that the distance between the inner sides of the second cylindrical part and the third cylin- drical part, corresponds to the distance between the outside and the inside of the pipe.

When the pipes in question are corrugating, the third cylindrical part, i. e. the outer lip, will only be able to surround part of the corrugating parts of the pipe.

The sleeve has to be designed such that the inside diameter in the sleeve fits a pipe which is to create an inlet or branch pipe. Typically, the delivery pipe or the branch pipe will be pipe standard commodity, which is why the sleeve can be made in a series of sizes with fixed intervals corresponding to the diameter of pipe on the market. In order to provide the sleeve with a certain strength, it is necessary to have a certain wall thickness depending on the material, therefore, the hole that is drilled in the pipe where the sleeve is adjusted, has to have a certain diameter, larger than the diameter of the delivery pipe such that there will be room for the sleeve's wall thickness.

The conical part of the sleeve which has to adjust to the slightly oval shape that arises during the cylindrical perforation of the pipe, must have an extension in the sleeve's longitudinal axis corresponding to the wall thickness of the inside part of the pipe, in which the sleeve has to be adjusted. This means for double walled pipes the inside pipe, and for corrugating pipes the pipe itself on which the corrugation is mounted.

Mounting the sleeve is performed similarly as for other sleeves of this type. Firstly, the place on the pipe is identified where a branch pipe or an inlet is to be mounted. Here- after, a cylindrical hole is drilled with diameter corresponding to the outside diameter of the pipe which is going to create inlet or branch pipe plus twice the wall thickness of the sleeve. Possible burrs and irregularities in the pipe are carefully removed with a file. Hereafter, the sleeve is mounted in which because of the material's flexible char- acter can be massaged in place, such that it is ensured that the conical part of the sleeve and the lips are arranged correctly about and in the pipe. Before placing the delivery pipe or the branch pipe, one will typically lubricate the inside of the sleeve with a suitable lubricant. Hereafter, the delivery pipe or the branch pipe can be mounted in the sleeve.

In order to obtain flexible characteristics such that a long durability for a sleeve of this type is achieved, the sleeve according to the invention can be produced in modified rubber, for example a SBR-rubber, an EPDM-rubber, a NPR-rubber or other similarly suitable rubber types. In certain embodiments the sleeve can also be made from a suit- able thermoplastic material.

In the following, a more detailed example on an invention according to the present description will be provided with reference to the enclosed drawings.

Fig. 1 shows a sleeve according to the invention, Fig. 2 shows the sleeve mounted in a double walled pipe, Fig. 3 shows a sleeve mounted in a corrugated pipe, and Fig. 4-8 shows the individual steps of the mounting of a sleeve according to the in- vention, in a corrugated pipe.

In figure 1 a sleeve 1, according to the invention, is shown. The outside 2 of the sleeve is divided into four different zones. A first cylindrical part 4 with an outside diameter corresponding to the hole drilled in the pipe or the well, wherein the sleeve is to be mounted, is continuous with a conical part 5 which has a diameter at the one end cor- responding to the diameter of the first cylindrical part, and at the other end it has a diameter which is larger than the diameter of the cylindrical part. The conical part is then connected with a second cylindrical part 6 which has a diameter which is larger than the largest diameter in the conical part. Hereby, an outside 2 arises consisting of a cylindrical part and a conical part which end with an element resembling a lip. In the mounting situation which is shown in figure 2 and 3, the sleeve 1 is arranged in the hole in the pipe in such a way that the lip element 6 surrounds the hole on the inside of the pipe. Thus, the conical part 5 of the sleeve 1 will be arranged along the edge of the hole. Because of the conical shape, the sleeve will adjust to the slightly oval shape which the hole in the pipe or the well will have been given, when drilling the hole in the pipe or the well with a circular drill.

At the opposite end of the lip-shaped element 6 a second lip-shaped element 7 is ar- ranged, which element has an outside diameter that is larger than the diameter of the first cylindrical part. The second lip-shaped element 7 is arranged to surround the out- side part of the pipe and the distance between the lips 6 and 7 which are comprised of the conical part 5 and the first cylindrical part 4, therefore corresponds to the wall thickness of the pipe or the well. Typically, the extension of the conical part 5 in lon- gitudinal direction 9 of the sleeve 1 will correspond to the wall thickness of the inside pipe. The extension of the first cylindrical part 4 in the sleeve's 1 longitudinal direc- tion 9 will typically correspond to the diameter of the corrugating or double walled part of the pipe.

In figure 2 the sleeve 1 is shown mounted in a double walled pipe 10. The inside of the pipe is facing downward on the figure. As it appears from the figure, the conical part 5 rests against fitting upon the inside part 11 of the pipe 10 in a tight fit. The lip part 6 surrounds the hole on the inside all the way around the circumference of the pipe. Cor- respondingly, the lip part 7 surrounds the circumference of the hole in the entire cir- cumference of the hole along the outside part 12 on the double walled pipe. The cylin-

drical part 4 of the sleeve 1 and the conical part 5 are designed in such a way that the wall thickness of the pipe 10 fits exactly between the two lip parts 6,7. Hereby, a tight fitting sleeve is made for a possible branch pipe or an inlet. The conical part 5 of the sleeve 1 compensates for the oval shape arising when drilling a circular hole in a cir- cular pipe.

In figure 3 a sleeve 1 mounted in a corrugating pipe is shown. The pipe consists of an inside pipe side 13 and the corrugating part 14 which often has the function of rein- forcing the pipe itself. The sleeve is correspondingly, as described in connection with figure 2, mounted in the pipe's wall.

The mounting of a sleeve according to the invention is illustrated in figures 4-8 and takes place by locating the place on the pipe or the well where a branch pipe or an inlet is to be placed. Thereafter, a hole is drilled figure 4 corresponding to the outside di- ameter of the cylindrical part 5 of the sleeve figure 5. Hereafter, the sleeve 1 is mounted in the recently drilled hole, and it is ensured that the lip parts 6 and 7 cor- rectly surrounds respectively the inside figure 7 and the outside figure 6 side of the circumference of the recently drilled hole.

Before the delivery pipe is placed in the sleeve, this is normally lubricated with a suit- able lubricant, for example acid-free vaseline or regular pipe grease. Hereafter, the branch pipe or the delivery pipe is mounted, figure 8.

The inside of the sleeve, see figure 7, is designed in such a way that a sealing lip 15 will adjust the circumference of the pipe flexibly, when the pipe is mounted in the sleeve 1. The pipe is pushed into the sleeve past the sealing lip 15 forward to the stop 16 where after the pipe is correctly mounted inside the sleeve.

The sleeve is typically made from a modified rubber material; SBR-rubber, EPDM- rubber, NPR-rubber or other suitable rubber types which have the necessary strength to maintain the pipe and characteristics of material which makes it suitable for resist- ing the fluids which the rubber sleeve possibly may be exposed to. For certain appli- cations where the demands for the tightness of the assembling are not so high, the sleeve can advantageously be made from a thermoplastic material.