The invention relates to a shut-off valve for installation on the outlet end section of a pipe from which is flowing a fluid, comprising a housing and a body which is provided rotatably about an axis of rotation in the housing, wherein the housing has an inlet and an outlet, and the body has a through-going hole, and in the open position of the valve, the inlet and the outlet and the hole together form a cylindrical flow channel whose cross section is at least as large as the external cross section of the pipe, and in the closed position of the valve, the body is turned in such a way that the hole extends transversely relative to the longitudinal axis of the inlet and the outlet.

A previous method is known for attempting to stop the discharge of fluids, e.g. oil or gas which are flowing out of a well pipe of oil wells, whereby a valve, e.g. of the above-mentioned type, is arranged at the well pipe. Since the pressure of the fluid in the ground and thus the velocity of the discharging fluid can be very high, in addition to which the well may be on fire, an installation of this kind can be extremely difficult and awkward to perform, a great deal of rig equipment being required. Furthermore the installation is time-consuming, thus entailing the risk of major damage to the environment until the fluid flow is stopped. It is evident that in this situation, any attempt to pass such a valve through the discharging fluid will be extremely difficult to perform in practice, just as it will be difficult to attach such a valve quickly to the pipe.

A further previous method for attempting to stop the fluid flow is by compression of the well pipe, but even if this were possible it does not provide a reliable shutting off of the fluid flow.

The object of the invention is to provide a valve of the above- mentioned type which is not encumbered with the above-mentioned disadvantages.

The characteristics of the shut-off valve according to the invention are characterized by the features in the claims presented.

In the following section the invention will be described with reference to the drawing which illustrates schematically an embodiment of a shut-off valve according to the invention.

Fig. 1 shows a side view of a shut-off valve provided on a well pipe.

Fig. 2 is a section along line II-II in fig. 1.

Fig. 3 is a perspective view of a shut-off valve whose two main components have been separated from each other and sections of the valve housing have been cut away.

Fig. 4 is a perspective view of the valve's inlet, with sections partially cut away.

In the figures there is illustrated a pipe 1 which projects vertically up from the ground, and which may, for example, be a well pipe, which is connected with a subterranean oil or gas reservoir, and on which is provided a shut-off valve according to the invention.

The shut-off valve comprises a valve housing 2 with a cylindrical section 3 with a cylindrical bore 4 (fig. 2) sealingly receiving a cylindrical valve body 5 which can be turned about its longitudinal axis in the bore 4. The valve housing 2 has an inlet section 11 and an outlet section 12 , hereinafter called inlet and outlet, which are composed of respective, diametrically opposite pipe connections which are located in the central area of the cylindrical section 3 of the

valve housing ^* 2, and which extend radially away from this in opposite directions. The valve housing 2 further comprises two transverse, circular, flat end plates 13, 14 which are sealingly screwed on to the respective ends of the cylindrical section 3 of the housing 2.

The outlet 12 can be provided with a flange 21 for connection of the valve to a pipe arrangement for transporting the well fluid away from the well after the valve has been installed and shut off.

As is best illustrated in fig. 2, there are provided in the inlet 11 two in cross section semi-circular in cross section wedge pieces 22, 23, which extend in the longitudinal direction of the housing's inlet 11 and in a longitudinal section have a radially inward facing side, which extends parallel to the inlet's 11 longitudinal axis and a radially outward facing side which simultaneously extends towards the inlet's longitudinal axis and away from the valve, the internal diameter of the wedge pieces corresponding to the outer diameter of the pipe 1, and their greatest external diameter approximately corresponding to the internal diameter of the abutting section of the housing's inlet. The concave sides of the wedge pieces each face their own way in the longitudinal direction of the housing.

As illustrated in fig. 1, between the end section of each wedge piece 22, 23 facing away from the housing and the section of the cylindrical section 3 of the housing facing this, there is provided a linear actuator 24, e.g. a screw jack or a hydraulic or pneumatic working cylinder for moving the wedge pieces 22, 23 along the longitudinal axis of the inlet.

When the wedge pieces 22, 23 are initially provided in the inlet 11 and near the central section of the housing as illustrated by dotted lines in fig. 2, the pipe can be inserted into the inlet 11, whereupon movement of the wedge pieces 22, 23 along the pipe 1 and away from the central section of the

housing causes the inlet 11 and the pipe 1 to be wedged tightl together.

By means of a suitable arrangement of a packing 25 between, e.g., a radially inward projecting flange 26 of the inlet near its outer end and a radially outward projecting flange 27 of the wedge pieces, a sealing connection can be obtained between the wedge pieces and the inlet.

After wedging, the wedge pieces can if necessary be welded to the well pipe, e.g. by providing a vessel around the well pipe (not shown) , filling the vessel with water, and using underwater welding in order to prevent ignition of the well fluid if this is inflammable.

The valve body has a through-going cylindrical hole 31 which, together with the housing's diametrically extending inlet 11 and outlet 12, form a cylindrical flow channel, whose cross section is at least as large as the external cross section of the well pipe 1.

An operating arm 32 is permanently connected to one end sectio of the valve body via a shaft 37 which extends centrally through one plate 1 . By moving the arm and turning the valve body, the valve can be brought into the closed position, since the valve body's bore then extends across the longitudinal axis of the inlet and the outlet.

In order to enable the valve to be placed on the well pipe 1 and its components passed across the pipe's longitudinal axis without having to pass them through any fluid which may be flowing out of the well pipe, both the valve housing 2 and the valve body 5 consist of two parts 33, 34 and 35, 36 which can be joined, as illustrated in fig. 3. The valve housing 2 is thereby split along a plane which extends diametrically in relation to the inlet 11 and the outlet 12 and which corresponds to the diametrical plane between abutting sections of the two wedge pieces 22, 23. The two halves of the housing

33, 34 have respective flanges 41, 42 which extend along this plane, and which permit the sealing connection of the two halves of the housing when the valve is installed. Thus, by means of axial movement of the two halves of the housing 33, 34 towards the well pipe's longitudinal axis, the housing halves can be joined without any edge sections of the inlet 11 or the outlet 12 coming into contact with the flow of fluid from the well pipe.

The housing is thus divided along a plane which intersects the cylindrical flow channel through the valve along two diametrically extending generatrices when the valve is installed.

The valve body is divided along two planes which comprise the respective, above-mentioned generatrices, and which extend in the valve body's longitudinal axis in one direction away from the through-going hole 31 which constitutes the flow channel in the valve body 5. There is thereby formed in the first valve body half 36 a groove 44 with parallel sides facing each other, and the other valve half 35 is in the shape of a disc, the width of which corresponds to the width of the groove 44 in the first valve body half 36.

The operating arm 32 is connected with the first valve body half 36 via the shaft 37. This valve half is therefore rotatable, but only very slightly movable axially in its longitudinal direction in relation to the related valve housing half 34. In order to also attach the other valve body half 35 to the related housing half 33 in the same manner, to permit axial movement on movement of the housing 2, there extends centrally through a hole in the plate 13 of this half a locking screw which is screwed into the valve half.

If the two parts of the shut-off valve have to be connected to a well pipe, they are initially located on each side of the well pipe's longitudinal axis, as illustrated in fig. 3, and gradually moved towards this, the valve body halves being

turned to the position they occupy when the valve is in the open position and the longitudinal axes of the valve hole, inlet and outlet halves and the well pipe are located on the same plane.

The valve halves are then moved towards each other until the second valve body half 35 slides into the groove of the first valve body half 36. By securing the operating arm in the above- mentioned position of the valve body parts in order to prevent rotation of the first valve body half, the second valve body half is thereby secured, thus preventing it from rotating inadvertently.

The valve halves are then moved closer towards each other until the two wedge pieces 22, 23 are located near the well pipe 1, the housing's flanges 41, 42 abut against each other and the flow channel which is formed by the two valve halves extends coaxially with the well pipe's longitudinal axis. Thereafter the housing's flanges 41, 42 are connected with each other by means of screws and nuts (not shown) , whereupon the wedge pieces 22, 23 are forced out of the inlet by means of the actuators 24 and wedged firmly between this and the well pipe, whereupon the wedge pieces may be welded to the well pipe.

By turning the operating arm 32 the valve body 5 can now be brought into the closed position.

If it is necessary to replace the shut-off valve by other equipment, drilling mud can first be introduced into the well pipe, e.g. via a valve 46 which is illustrated schematically in fig. 1, while the valve is kept closed, whereupon the shut-off valve can be removed.

Even though the above description involves a valve body which is divided along two parallel planes, and the valve housing is divided along one plane, these components can instead be divided in a different manner, provided that the valve parts can still be joined and attached to the well pipe without any

section of the valve coming into contact with the well fluid during installation of the valve. Thus the valve body can, for example, be divided along two planes which extend at a slight bending angle to each other, thereby obtaining two valve body parts which are principally nonrotatably connected with each other to prevent turning, but only abutting completely with each other at the conclusion of the joining movement, a factor which facilitates the joining process.

The valve body can further be divided along the same plane as the valve housing, in that the two valve body parts can have axially extending pins or holes to fit the pins in order to ensure nonrotatable connection with each other during installa¬ tion.

Instead of only two wedge pieces, more can be provided. Alternatively the housing halves can have flanges which are adapted to fit the well pipe's flange, and which, immediately after the joining of the valve halves, are sealingly welded to the well pipe.

In order to ensure the correct and stable transport of the valve halves' towards the well pipe, these can be mounted on rails which are adjusted correctly in relation to the well pipe, on which the valve halves are manoeuvered and at the same time may be conveyed towards the well pipe.

As illustrated in fig. 4 there can be provided in the shut-off valve's inlet 11 in the area of the mud valve 46 a device for cutting off that section of the well pipe which projects into the shut-off valve and over the wedge pieces 22, 23.

This device comprises a circular ring 47 whose ring plane extends perpendicular to the inlet's longitudinal axis, and slidingly in a radially inwardly open, circular groove which is provided in the radially inward facing wall of the inlet 11.

As in the case of the valve housing 2, the ring 47 is divided along a plane which extends diametrically in relation to the inlet 11. Before installation of the shut-off valve the two ring halves are located in the grooves of the respective halve of the inlet. When the two halves of the inlet are joined during the installation of the shut-off valve on the well pipe the end sections of the ring halves are brought close to each other, thus enabling movement of one ring half to cause movement of the other ring half in the related groove in the inlet halves.

Alternatively, the end sections of the ring halves can, e.g., consist of pins or holes which fit the pins, thus enabling the pins and holes to engage with each other during the installation of the shut-off valve on the well pipe 1.

On a periphery the ring 47 has teeth, and on rotation of the ring, sections of the peripheral area can be successively brought into the opening for the pipe connection on to which the mud valve 46 is attached. The teeth of the ring are arranged to engage with the teeth of a toothed wheel of a driving device for rotation of the ring, this toothed wheel being introduced through the pipe connection.

A cutting tool, e.g. a knife 48, is pivotally connected at one end to the inside of one ring half, the knife being capable of pivoting on the ring plane. The length of the knife is no greater than will allow the knife 48 to be completely pivoted away from that area of the shut-off valve which is occupied by the well pipe when the shut-off valve is installed on it and the well pipe projects over the ring 47. The knife 48 has an edge which faces the well pipe when the knife is located in this pivoted away position.

Between the other end section of the knife 48 and the ring half to which it is connected, there is provided a device, e.g. a compression spring 49 which attempts to swing the knife away from this position, i.e. towards the inlet's longitudinal axis.

Thus when the ^' shut-off valve is installed the knife will initially abut against the well pipe's outer wall and then be forced into the above-mentioned, pivoted away position. After completion of the installation of the shut-off valve and on rotation of the ring 47 by means of this drive device, the upper section of the well pipe can be cut off.