TECHNICAL FIELD

The present invention relates to a device for opening a branch of a pipeline, comprising a shaft, a cutting body, attached to the shaft, a motor configured to rotate the shaft, a support body rotably attached to the shaft adjacent the cutting body, wherein the support body is eccentric with regard to a centre axis of the shaft and has an outer peripheral support surface configured to bear against an inner peripheral surface of a pipeline branch, and an elongated element connected in a first end to the support body and configured for controlling the position of the support body through manoeuvring of a second end of the elongated element.

BACKGROUND

In connection to the opening of a branch to a pipeline, in which the pipeline is provided with a liner, typically in connection to the renovating of buildings, a drilling tool is introduced into the branch and is used for drilling a hole in the liner of the pipeline. Typically, the branch has curvature and connects to the pipeline with an angle other than perpendicular. The branch may have a generally circular cross-section. This means that the hole into the pipeline will need to be oval if a residual flange is to be avoided where the branch opens up into the pipeline.

EP 2 545 317 discloses a device aimed for such opening of a branch section closed in connection to the renovation of a pipeline. However, if residual flanges are to be avoided where the branch connects to the pipeline, the cutting body and a support body, which can be applied as a support against an inner wall of the branch, must define a cross-section corresponding to the diameter of the branch. Such dimensioning of the support body and the cutting body will make it very difficult to introduce the device into the branch all the way to the pipeline, especially if the branch has a curvature. THE OBJECT OF THE INVENTION

It is an object of the present invention to provide a device for opening a branch to a pipeline which is able of cutting an oval opening, due to an angle between branch and pipeline, such that no residual flange is left, and which can be easily introduced into the branch all the way to the pipeline. SUMMARY

The object of the invention is achieved by means of a device for opening a branch of a pipeline, comprising

- a shaft, - a cutting body, attached to the shaft,

- a motor configured to rotate the shaft,

- a support body rotably attached to the shaft adjacent the cutting body, wherein the support body is eccentric with regard to a centre axis of the shaft and has an outer peripheral support surface configured to bear against an inner peripheral surface of a pipeline branch, and

- an elongated element connected in a first end to the support body and configured for controlling the position of the support body through manoeuvring of a second end of the elongated element, said device being characterised in:

- that the cutting body has a perimeter which is variable and depending on the centrifugal force generated on the cutting body upon rotation of the shaft, and wherein the perimeter has a maximum radial distance r1 from a centre axis of the shaft, - that the peripheral support surface of the support body is at a radial distance r2 from the centre axis of the shaft, and that r2>r1.

The elongated element is flexible and configured to allow the bending thereof in connection to the introduction thereof into and movement thereof through a pipeline branch having a curvature. The perimeter at which the maximum radius r1 is defined is the perimeter achieved upon rotation of the shaft with a rotational speed that results in a maximum perimeter being defined by the cutting body. Preferably, the cutting body is configured to generate a symmetric, circular perimeter at such rotational speed.

According to one embodiment, the cutting body comprises a chain, wherein the chain defines the perimeter of the cutting body. Alternative embodiments may comprise foldable pins, extendable cutters or the like, instead of a chain.

According to one embodiment, the chain defines an annular body, attached to the shaft via a plurality of attachment members, each attachment member being attached in one end to the shaft an in an opposite end to the annular body defined by the chain. Preferably the device comprises at least three, preferably at least four such attachment members, attached to the annular body with preferably equal distance to each other along the periphery of the annular body.

According to one embodiment, the shaft or an element in alignment with the shaft protrudes through the support body.

The attachment members allow the distance between the chain and the shaft to vary up to the maximum radius r1 of the perimeter defined by the chain upon rotation of the shaft at a rotational speed such that each attachment members are extended to a maximum in a radial direction with regard to the shaft. Thereby, the annular body defined by the chain has a generally circular cross-section with a centre axis in alignment with the longitudinal axis of the shaft. According to one embodiment, the attachment members comprise chain links, linked to the links of the chain forming the annular body and linked to a body connected to the shaft. Alternative embodiments of the cutting body may include solutions in which at least one chain is attached in opposite ends thereof to the shaft, at attachment points separated from each other in the longitudinal direction of the shaft. According to certain embodiments, one of the attachment points may be slidingly arranged on the shaft. Thereby, upon rotation of the shaft, due to the centrifugal force on the chain, the slidingly arranged end will move towards the other end, and the perimeter and radius will increase up to a maximum, resulting in achievement of the maximum radius r1 for such a solution. The slidingly arranged end may be attached to a ring arranged on the shaft and able of sliding in the longitudinal direction of the shaft. Solutions with non- slidingly arranged ends are also possible, wherein the length of the chain is larger than the distance between the attachment points where the ends of the chain are connected to the shaft.

According to one embodiment, - the shaft comprises a flexible wire,

- the cutting body is arranged at a first end of the shaft,

- the motor is arranged at an opposite second end of the shaft, and

- the elongated element is a tube which is coaxial with the shaft and encloses the shaft.

According to alternative embodiments, the motor is arranged adjacent to the support body and the cutting body, and may be an electric motor or fluid motor, wherein an elongated flexible electric conductor or an elongated flexible conductor for conduction of pressurised fluid is arranged for providing the motor with its driving source. The elongated element to which the support body is connected may comprise a tube coaxial with and enclosing the electric conductor or the fluid conductor, or may comprise the fluid conductor itself.

The shaft can thus be bent and thereby easily introduced through a pipeline branch which has a curvature. Provided that the shaft is long enough, the motor does not need to be positioned inside the pipeline branch during operation of the device. The shaft is able to rotate inside and in relation to the tube formed by the elongated element. According to one embodiment, the support body is attached to an outer periphery of the elongated element.

According to one embodiment, the support body is attached to a first end of the elongated element, and there is provided a manoeuvring handle in an opposite second end of the elongated element. Thereby, rotation of the support body can be easily executed from a remote position outside a pipeline branch in which the cutting body operates.

According to one embodiment, the device comprises a cutting head connected to an end of the shaft adjacent to the cutting body and defining a perimeter which has a maximum radius r3, wherein r3<r1. The cutting head is thus arranged in front of the cutting body and may be used for cutting a first hole in a liner and for stabilising the position of the cutting body. The cutting head has a radius which is small enough not to obstruct the introduction of the device into a pipeline branch. According to one embodiment, the device comprises a camera attached to the support body. By means of a camera it will be possible to detect if there is any residual flange remaining and that the cutting body is positioned and operating correctly. BRIEF DESCRIPTION OF THE DRAWING

Exemplifying embodiments of the invention will hereinafter be described more in detail with reference to the annexed drawing, on which,

Fig. 1 is a perspective view of a part of a device according to a first embodiment,

Fig. 2 is a perspective view of the part of the device shown in fig. 1 , from another direction, Fig. 3 is a side view of the part of the device shown in figs. 1 and

2,

Fig. 4 is an end view of the part of the device shown on figs. 1-3,

Fig. 5 is a perspective view of a part of a device according to a second embodiment,

Fig. 6 is side view of the part of the device shown in fig. 5, and

Fig. 7 is a perspective view of a second part of any of the devices shown in figs. 1-6.

DETAILED DESCRIPTION

Figs. 1-4 in combination with fig. 7 show a first embodiment of the device according to the invention.

The device comprises a shaft 1 , a cutting body 2, attached to the shaft 1 , and an electric motor 3 configured to rotate the shaft 1. Adjacent the cutting body 2, a support body 4 is rotably attached to the shaft 1 via an elongated element 5 formed by a flexible polymer tube 5 which is coaxial with the shaft 1 and encloses the shaft 1. The tube 5 and the shaft 1 protrude through a hole in the support body 4. There is also provided a cutting head 6 connected to a first end of the shaft 1 adjacent to the cutting body 2.

There is a distance between the point at which the cutting body 2 is attached to the shaft 1 and an adjacent first end of the tube 5 where the support body 4 is connected to the tube 5. Between said point and said first end of the tube 5 there is provided a spring member 7 that encloses the shaft 1 and gives support to the latter, while at the same time functioning as a distance element between said point and said first end of the tube 5. The shaft 1 comprises a flexible wire 20. The cutting body 2 is arranged at the first end of the shaft 1 , and the motor 3 is arranged at an opposite second end of the shaft 1 . At the second end of the shaft 1 there is provided a stand 8 on which the motor 3 is mounted. At a corresponding second end of the tube 5, adjacent the second end of the shaft 1 , there is provided a manoeuvring handle 9. The handle 9 is connected to the tube 5 via a transmission. In the embodiment shown, the transmission is hidden inside a box 10, and comprises a larger gear wheel connected to the handle 9 and a smaller gear wheel connected to the tube 5, said gear wheels being in engagement with each other. Upon turning of the handle 9, the tube 5 will rotate around its longitudinal direction, and the support body 4 will thus move correspondingly.

The stand 8 comprises a circular bottom ring 11 functioning as support against ground. The support body 4 is eccentric with regard to a centre axis of the shaft 1 and has an outer peripheral support surface 12 configured to bear against an inner peripheral surface of a pipeline or pipeline branch. The elongated element formed by the tube 5 is connected in said first end to the support body 4 and configured for controlling the position of the support body 4 through manoeuvring of the second end of the tube 5 via the handle 9.

The cutting body 2 has a perimeter which is variable and depending on the centrifugal force generated on the cutting body 2 upon rotation of the shaft 1. Upon rotation of the shaft above a predetermined rotational speed, the perimeter has a maximum radial distance r1 from a centre axis of the shaft. The peripheral support surface 12 of the support body 4 is at a maximum radial distance r2 from the centre axis of the shaft 1 , and r2>r1. Upon rotation of the shaft 1 during the cutting of a hole through a wall or liner of a pipeline, when the device is located in pipeline branch adjoining the pipeline, the device thus has a total maximum diameter d extending from the peripheral support surface 12 of the support body 4 to the diametrically opposite side of the cutting body 2. The device will thus have two support points against the surrounding wall of the pipeline branch, defined by the peripheral support surface 12 and the diametrically opposite side of the cutting body. By turning the tube 5 by means of the handle 9 during cutting of a hole, the support body 4 is moved around an inner periphery of the pipeline branch, thereby enabling the cutting of an oval hole in a liner of the pipeline to the which pipeline branch is connected with an angle other than perpendicular.

The cutting body 2 comprises a chain 13. Upon rotation of the shaft 1 , the chain 13 defines the perimeter of the cutting body 2. The chain 13 defines an annular body 19, attached to the shaft 1 via a plurality of attachment members 14. Each attachment member 14 is attached in one end to the shaft 1 and in an opposite end to the annular body defined by the chain 13. In the embodiment shown, the attachment members 14 comprise links attached in on end to a link of the chain 13 and in another end to a disc-shaped body 15 connected to the shaft 1. The attachment members 14 are angularly evenly distributed around the periphery of the chain 13. They have the same length. Accordingly, the chain 13 defines a circular annular body 19 upon rotation of the shaft 1 above a predetermined rotational speed. The centre axis of the circular annular body 19 defined by the chain 13 is in alignment with the longitudinal axis of the shaft 1.

On the chain 13 there are provided cutting members 16. In the embodiment shown in figs. 1-4, the cutting head 6 has a conical or frusto-conical shape. The alternative embodiment shown in figs. 5 and 6 in combination with fig. 7 differs from the one shown in figs. 1- 4 in that the cutting head 17 has a cylindrical shape. In both embodiments, the cutting head 6, 17 is connected to the first end of the shaft 1 adjacent to the cutting body 2 and defines a perimeter which has a maximum radius r3, wherein r3<r1. The cutting head 6, 17 stabilizes the position of the device as it engages the liner of a pipeline before the cutting body 2 reaches the position at which it starts cutting the liner.

The device further comprises a camera 18 attached to the support body 4. The camera 18 is preferably connected to a display, not shown. On basis of the information from the camera 18, an operator will be able to decide how to turn the handle 9 in order to achieve correct cutting of a hole of non-circular shape, typically oval shape, in a liner of a pipeline connected to a branch in which the device is positioned, such that no flanges are left at the transition between the branch and the pipeline.