Background Art A device of the type described by way of intro- duction is disclosed in WO 9858137, which relates spe- cifically to a device for a stop valve, which is buried in the ground and connected to a piping system. This device allows a valve arranged in the piping system to be taken up for the purpose of cleaning, renovating or exchanging parts without the need for labour-intensive and expensive excavation work.

One problem associated with this device is that, although the excavation work has been eliminated, it remains relatively expensive to change the parts located in the ground, and, furthermore, the device is more com- plicated and thus more expensive than a conventional valve. For example, a water work system in a residential district comprises a main pipe which has one valve for each branch pipe. This requires a large number of valves, many of which will very rarely or never be used, serving only as passages through which the water flows. Providing one device according to WO 9858137 for each of these valves would imply unnecessary costs.

Object of the Invention The object of the present invention is therefore to further develop the device according to WO 9858137 and to

provide a simplified and more flexible device, which allows the interruption time required to change a valve or the like to be reduced and the possibilities of in- spection and service of water systems and other liquid systems to be improved.

Summary of the Invention According to the invention, this object is achieved by means of a device of the type described by way of in- troduction, said device being characterised in that the adapter has a space which is defined by two opposite walls, the pipe access means being insertable in a direc- tion of insertion between said walls, each wall having an inner surface which is parallel to the direction of in- sertion and which has an opening, the openings of said inner surfaces being arranged opposite each other, and that the pipe access means has end surfaces which have a complementary shape to that of the inner surfaces of the adapter walls, each end surface having an opening along the circumference of which a groove extends, a resilient ring seal which projects past the groove being inserted therein; with the pipe access means inserted in the adapter, the ring seal bearing against the adapter in a sealing manner and the openings of the end surfaces being arranged opposite the corresponding openings in the adapter wall.

The advantage of the device of the invention is that it allows a pipe access means to be replaced in a simple and quick manner, since screws or other fixing means are no longer required for connecting the pipe access means to the adapter. The pipe access means may have different functions, as required, and because said means may be easily and rapidly replaced the device of the invention will be more flexible, which allows it to be used more economically considering the fact that the more complex valves have to be used only when they are really needed.

Moreover, the device of the invention may be advanta-

geously used in the food industry, for example in dairy plants, where valves which are used infrequently are sometimes unsuitable for reasons of hygiene as liquid may accumulate in pockets in said valves, implying, inter alia, a risk of bacteria developing therein.

To ensure an adequate operation, the adapter and the pipe access means have to be precisely matched in terms of dimensions, so that, in the inserted position, the inner surfaces of the adapter bear with an exact fit against the end surfaces of the pipe access means. A sealing 0-ring is arranged between said surfaces, said O- ring being pressed even harder against the adapter when a pressurized fluid pressing the 0-ring radially outward is present in the adapter and the pipe access means.

Preferably, the seal is an 0-ring, the cross-sec- tional diameter of which is larger than the depth of the groove and smaller than the width of the groove. To ob- tain an optimal sealing effect, the ratio of the cross- sectional diameter of the 0-ring to the depth of the groove should be in the range 1: 0.78-1: 0.82, preferably 1: 0.8, and the ratio of the cross-sectional diameter of the 0-ring to the width of the groove should be in the range 3: 3.5-3: 4.5, preferably 3: 4.

Furthermore, the end surfaces of the pipe access means and the inner walls of the adapter are preferably plane, thus facilitating the manufacture thereof, but they may, of course, also have an arched shape.

To facilitate the insertion of the pipe access means into the adapter, the inside of the adapter has, accord- ing to a preferred embodiment, upstream of the adapter space as seen in the direction of insertion, the shape of a funnel, and the end surfaces of the pipe access means are essentially square, the corners oriented in the in- serted position toward the bottom of the space being rounded.

Preferably, the adapter space has a bottom com- prising a shoulder, the pipe access means bearing against

said shoulder in the inserted, sealed position, which is the position in which the openings of respectively the adapter and the pipe access means are located opposite each other.

Below the shoulder, the bottom of the adapter space preferably has a dirt collecting space for collecting dirt which, during insertion, may accompany the pipe access means from the ground. Without this space, large dirt particles could prevent the pipe access means from reaching its sealing position.

According to a further embodiment, the pipe access means has the shape of a pipe having a tool holder which is arranged on the central part of the pipe shell, said tool holder allowing the attachment of a rod when in- serting the pipe access means into the adapter or re- moving it therefrom.

When the device of the invention is to be used in a water work system buried in the ground, the adapter has preferably, above the space, a connecting portion for connecting a sealed well pipe, which extends up to ground level and through which the pipe access means is insert- able.

When the pipe access means is provided with a tool holder, the means may be a valve comprising a valve spindle, which extends through the pipe shell and is non-rotatably connected to the tool holder, the tool holder being rotatable to enable operation of the valve spindle, which controls a adjusting means in the valve.

It is evident that the rod attached to the tool holder during insertion of the pipe access means may also be used to operate the valve. The valve may be a stop valve, a control valve or any other suitable valve depending on the application.

In alternative embodiments, the pipe access means has, on the inside, a flow-stopping transverse wall or a transverse wall provided with an opening for restricting the flow.

When the pipe access means is provided with a trans- verse wall, it preferably also has projections for con- necting an external functional unit on both sides of the transverse wall.

Said external functional unit may be a flow meter or a media outlet intended, for example, for venting pur- poses.

Brief Description of the Drawings The invention will be described below by means of one exemplifying, but non-limiting, embodiment, which is schematically illustrated in the accompanying drawings, in which Fig. la is a cross-sectional view in a direction of flow through an adapter in a device according to the in- vention; Fig. lb is a top view of the adapter of Fig. 1.

Fig. 2a is a cross-sectional view in a direction of flow through a pipe access means in a device according to the invention; Fig. 2b is a side view of the end surfaces of the pipe access means shown in Fig. 2a; Fig. 3a is a cross-sectional view with certain parts removed illustrating an 0-ring which is inserted in a groove in the end surface of the pipe access means; Fig. 3b is a cross-sectional view with certain parts removed illustrating the pipe access means and the 0-ring of Fig. 3a as inserted in an adapter; Fig. 3c is the same view as that of Fig. 3b, but illustrates the deformation of the 0-ring in the case where a pressurized liquid is present in the pipe access means and the adapter; Figs 4a-f illustrate alternative embodiments of the pipe access means; Fig. 5a is a schematic view of an adapter buried in the ground, said adapter being connected to a well pipe

and receiving a pipe access means without an internal transverse wall; Fig. 5b is the same view as that of Fig. 5a, the only difference being that the pipe access means is being removed from the adapter by means of a rod, which is attached to a tool holder on the pipe access means; Fig. 5c is the same view as that of Fig. 5a, the only difference being that the pipe access means of Fig.

5a has been replaced by a pipe access means having an internal transverse wall; and Fig. 6 is a view of a well pipe provided with a cover together with an adapter.

Description of a Preferred Embodiment The inventive device shown in the Figures comprises an adapter and a pipe access means.

The adapter 2 is intended to be connected to a liquid piping system and has, as shown in Fig. la, a wall 8 with two diametrically opposed openings 4 for connecting said adapter to pipes in the piping system.

A space 6 is provided between said openings, the pipe access means being adapted to be inserted in said space in a direction of insertion (arrow I). The space is defined in a direction perpendicular to the direction of insertion and in the direction of flow of the fluid by two plane inner surfaces 10 located opposite each other.

Each inner surface has a circular opening 12, said openings of the inner surfaces being located opposite each other. The openings 4 and 12 together form a through hole in the adapter wall.

The space 6 has a bottom 24, and a shoulder 18 extends upwards therefrom along the plane inner sur- faces 10.

Above the space, the inside of the adapter wall forms a funnel. The outside of the adapter wall has, above said space, a connecting portion 14 including a

shoulder 16 located above the opening 4 for connecting a well pipe.

Thus, the adapter forms an upwardly open element having a through passage in the horizontal direction and an interior space adapted to receive, for example, a valve, as described below.

The pipe access means 3 of Figs 2a and 2b has end surfaces 5, which like the inner surfaces of the adapter walls are plane and which are formed by rectangular flanges 5. Each flange has a circular opening 7, a circular groove 9 which is concentric with the opening extending round said opening and being intended to receive an 0-ring.

Between the flanges, a protrusion 11 for a tool holder is provided on the outside of the pipe access means.

The distance between the flanges is one or a few tenths of a millimetre smaller than the distance between the inner walls of the adapter.

Thus, the outer shape of the pipe access means are carefully matched to the dimensions of the adapter space as are the openings 7 of the pipe access means to the openings 12 of the adapter. However, the interior of the pipe access means may be designed in various ways.

Figs 3a-c show how the resilient 0-ring is deformed when the pipe access means is inserted in the adapter. In Fig. 3a, the O-ring 13 is inserted in a groove 9 provided in the inner surface of the pipe access means and pro- jects past the edge of the groove. The groove is rec- tangular in cross-section and slightly wider than the 0- ring. Preferably, the 0-ring is fixed in the groove, for example, by means of glue or grease (not shown) to pre- vent it from sliding out during insertion of the pipe access means in the adapter.

When the pipe access means is inserted in the adapter, as shown in Fig. 3b, the 0-ring, which is slightly ovally deformed, bears against the inner surface

of the adapter in a sealing manner. As shown in Fig. 3c, the pressure of the liquid 15 in the piping system causes further deformation of the 0-ring, which obtains an es- sentially square shape and is applied even harder against the adapter wall. In this position, the 0-ring is pressed radially outwards.

The inside of the pipe access means may be designed in various ways depending on the intended application.

However, on the outside they preferably have the same appearance in order to match the adapter and other tools and connecting units. In a preferred embodiment, as shown in Fig. 4a, a transverse wall 21 is provided on the in- side of the pipe access means, said wall obstructing the flow through the pipe access means. On the outside of the pipe access means there are provided two projections 23 for connecting a flow meter, air bleeds etc. (Figs 4d and 4e), said projections being arranged on both sides of the transverse wall and having such a thickness that threaded holes may be made therein. Between said projections, the pipe access means has a protrusion for a tool holder 11.

When the pipe access means is a valve (Fig. 4f) or when it is adapted to completely (Fig. 4c) or partially (Fig.

4b) allow the passage of a flow, the transverse wall is completely or partially removed.

Figs 5a-c show a well pipe which at its lower end is connected to the device described. In Fig. 5a, the flow through the pipe access means is unrestricted. To stop the flow through the means the flow is cut off at least upstream of said means. A rod is then attached to the tool holder of the pipe access means and the pipe access means is pulled up through the well pipe, as shown in Fig. 5b. A pipe access means provided with a flow-stop- ping transverse wall is then inserted in its place, as shown in Fig. 5c, whereupon the flow is again admitted, but cut off downstream of the pipe access means. The change is fast and simple and no further means, such as screws, are required to achieve a seal between the pipe

access means and the adapter. Thus, there is no reason to incorporate expensive stop valves into a water work system at all the points where the flow may, at some time or other, have to be cut off. The present invention allows a stop valve or the like to be mounted afterwards, if necessary.

Fig. 6 shows an adapter and a well pipe 20 provided with a cover 22. When burying the adapter in the ground, the well pipe is sealingly connected thereto.

It will be appreciated by the person skilled in the art that the device described above is only one possible embodiment and that, alternatively, it could be used also in the process industry, in particular in the food proc- essing industry, for example in dairy plants, in which case well pipes and other parts intended for systems buried in the ground obviously are not needed.