The present invention relates to an overflow for a building which exhibits a waste pipe extending through a floor, comprising at least one evacuation opening intend¬ ed to be located in the floor level area and be connect- ed to the bore of the waste pipe to enable the runoff of water from the floor through the waste pipe by the inter¬ mediary of an odour trap, an upper inlet end which is connectable to an upwardly extending upper waste pipe terminating above floor level, a lower outlet end which is insertable into a downwardly extending lower waste pipe, and both a drainage passage extending between the inlet end and the outlet end, and an evacuation passage extending between the evacuation opening and the outlet end. Background of the Invention

Sanitary rooms, such as toilets, bathrooms and the like, are normally provided with a watertight floor covering which is extended about 10 cm up the surround¬ ing walls and up extra raised thresholds. This is done to prevent water damage in the event of a hose, a valve or a pipe leaking. However, in order for water damage to be prevented in this manner in the case of a possible leak, it is necessary that an outlet placed low down, a floor drain or the like, through which the water can be evacuated, be located in the sanitary room. Some types of sanitary rooms, such as for example toilets without a bathtub or a shower, often do not have an outlet placed low down in the room. In addition, there are sanitary rooms with shower cubicles where the outlet in the shower cubicle is located higher up than the upper edge of the threshold, which, in the case of a leak, means that, instead of being evacuated through the outlet, the water flows over the threshold in the doorway and out into the rest of the building.

A toilet, which in addition to normal toilet func¬ tion, exhibits evacuation openings placed low down at floor level around the circumference of the outlet of the toilet, is known from FR 749,747. The evacuation openings are supposed to function as a floor drain for a shower immediately adjacent to the toilet. The regular water seal of the toilet is utilised as an odour trap for the evacuation openings.

A construction such as this would not be suitable for use purely as an overflow. It would be exorbitantly expensive to purchase and too difficult and costly to install because of the fact that the bends of the water seal would have to be built into the floor.

A trunk sewer centre with a design according to the preamble of claim 1 of the present application is known from SE 342 857. In addition to exhibiting an evacuation opening, it constitutes a kind of branch coupling, to which pipes can be connected from different outlet sources. However, this device exhibits a bulging or a diameter-enlarged portion, with a diameter which is con¬ siderably larger than that of the waste pipe with which it is intended to be connected, in the area where the branches connect to the central drainage passage. This bulging is intended to be set in a floor framework and, therefore, the branch coupling has to be installed in connection with the construction of the building or in connection with a major renovation since the installation requires major intervention in the floor structure.

There is also a need for an overflow for dishwashers and washing machines, for example, which are located in rooms which do not have a watertight floor covering. With respect to dishwashers it is known to place these on a tub-like collecting vessel made of plastic so that the water in the dishwasher is collected in the event of a leak in the dishwasher. The intention is that, in this way, an occupier of a flat, for example, will notice the leak even when the dishwasher is built into the kitchen,

because the water is allowed to flow out onto the floor in front of the dishwasher instead of down into the floor underneath kitchen cupboards and the like. In order for this type of plastic tub to provide any protection against water damage, it is necessary that the occupier is at home at the time and is able to notice the leak. Summary of the Invention

The object of the present invention is to overcome the above-mentioned problems and drawbacks and to provide an overflow which is generally applicable to all rooms which exhibit a waste pipe extending through a floor. Another object of the invention is to provide an overflow which is simple and inexpensive to manufacture and which has the form of an attachment which is quickly and easily installable in existing drainage installations. At a minimum, these objects are achieved be means of an over¬ flow according to claim 1.

The basis of the invention is thus the realisation that a simple, effective, inexpensive and quickly in- stallable overflow can be achieved by inserting into a waste pipe, cut off or terminating at floor level, a tubular attachment exhibiting evacuation openings which are connected to an inner bore and which are intended to be located close to or at floor level, and by connecting the upwardly extending part of the waste pipe to the top part of the attachment. This would not be possible with a branch coupling according to the above-mentioned SE 342 857, because if the outlet end of the branch coup¬ ling is pushed down as far as possible into a waste pipe cut off just below or at floor level, i.e. until the waste pipe or the floor surface hits against the bulging around the water seal of the branch coupling, the evacua¬ tion openings of the coupling will be located at a large distance above floor level and therefore cannot function as an overflow.

In order to prevent the emanation of unpleasant odours from the waste pipe, the evacuation passage has

to be connected to the waste pipe by the intermediary of some type of odour trap. Conveniently, this odour trap has the form of a water seal, but mechanical odour traps are also a possible choice. Optionally, the odour trap may be shared by the drainage passage and the evacuation passage but it can also be provided for the evacuation passage only. The advantage of the latter alternative is that in the event the odour trap becomes plugged, the drainage passage will not be blocked. In a design with a joint odour trap, which is the case in the above-men¬ tioned FR 749,747, there is a risk that the wastewater will flow out onto floor through the evacuation openings in the event of the odour trap becoming plugged. In an odour trap in the form of a water seal, some kind of filler conduits should be arranged between the bore of the waste pipe and the water seal to enable small quanti¬ ties of water from the waste pipe to flow into the water seal so that it will always be filled with water. This is necessary because, normally, water flowing through the evacuation passage will be a very rare occurrence and, therefore, there is a risk that the water in the water seal will evaporate if it is not being replenished conti¬ nuously.

In a preferred embodiment of the present invention, the attachment has the form of two essentially concentric pipes with a circular cross-section, the drainage passage being located in the central pipe while the evacuation passage is located in the peripheral pipe. Preferably, the central and peripheral pipes are detachable from each other in order to make manufacturing, installing, and dismantling, for example when cleaning, easier.

If the water seal is arranged in the evacuation pas¬ sage only, it may suitably be located between the peri¬ pheral and central pipe in the form of a flute. In a pre- ferred embodiment of the invention, the central pipe exhibits a taper in its lower part in order to provide

more room for the water seal and thereby a higher flow rate of the evacuation passage.

Suitably, the evacuation openings can be formed in a flanged portion in the upper part of the attachment, which portion has a larger diameter than the lower waste pipe. The underside of the flanged portion will then be abutting against the floor and, in order to avoid water penetration, a seal in the form of e.g. rubber or glue can conveniently be arranged between the flanged portion and the floor. However, that part of the attachment which is below the flanged portion has a diameter which is smaller than the inner diameter of the lower waste pipe. As a result, the whole of the lower part of the attach¬ ment is insertable into the lower waste pipe until the flanged portion abuts against the floor surface or the edge of the lower waste pipe.

If the room has a floor covering in the form of a carpet, this may suitably be folded down into the waste pipe a certain distance for increased protection against water leaking down into the floor. In addition, it is preferred to arrange a seal, e.g. an O-ring, between the outer circumference of the attachment and the inside of the waste pipe.

In one embodiment, the overflow is especially de- signed to function as an overflow for a dishwasher, a washing machine or the like. This can conveniently be achieved by the machine being placed in a tub-shaped container, which by means of a pipe is connected to an overflow according to the invention. Brief Description of the Drawings In the drawings : FIG. 1 is a cross-section of a floor portion with a waste pipe extending through it and an overflow in the form of an attachment according to a first embodiment of the invention,

FIG. 2 is a cross-section according to Fig. 1 with an overflow according to a second embodiment,

FIG. 3 is a cross-section according to Fig. 1 with an overflow according to a third embodiment, FIG. 4 is a cross-section according to Fig. 1 with an overflow according to a fourth embodiment, FIG. 5 is a cross-section according to Fig. 1 with an overflow according to a fifth embodiment, FIG. 6 is a cross-section according to Fig. 1 with an overflow according to a sixth embodiment having a mechanical odour trap, FIG. 7 is a perspective view of a drainage installa¬ tion from a sink having an overflow which is shown with its respective parts detached from one another, and FIG. 8 is a cross-section according to Fig. 1 with an overflow which is especially adapted to func¬ tion as an overflow for a dishwasher, a washing machine or the like. Description of Preferred Embodiments of the Invention Reference is first made to Fig. 1, which shows a cross-section of a first embodiment of an overflow ac¬ cording to the present invention. The reference numeral 1 indicates a subfloor, which on its top surface is covered with a floor covering 2. This covering may advantageously be a conventional plastic or linoleum carpet which is applied to the floor in a watertight arrangement with welded seams and edges extended up the surrounding walls. The reference numeral 3 indicates a lower waste pipe ex¬ tending downwards through the floor from the area flush with the top surface of the subfloor. The floor carpet 2 is folded down a certain distance into the lower waste pipe along its upper circumference.

The overflow has the form of an attachment which exhibits evacuation openings 4 and is inserted by a lower outlet end 5 into the lower waste pipe 3 and is connected by an upper inlet end 6 to an upwardly extending upper waste pipe 7.

The overflow is generally cylindrically formed and comprises an inner pipe 8 which delimits a central drain¬ age passage 9 and an outer pipe 10 which surrounds the inner pipe and delimits a peripheral evacuation passage 11 between an inner side and the outside of the inner pipe. At its lower outlet end 5, the inner pipe 8 has a flange 12 flanged outwards, which consists of a bot¬ tom portion 12' directed outward and a side portion 12" directed upward in the outer edge of said bottom portion. The outer pipe 10 is tapered at its lower outlet end and when the overflow is assembled, the lower edge of the outer pipe will be located inside and lower than the upper edge of the side portion 12". In this way, the flange 12 and the outlet end of the outer pipe will form a water seal which prevents an unpleasant odour from escaping into the room through the evacuation passage 11.

As can be seen from the Figure, the central pipe 8 also exhibits a taper about level with its lower quarter point. This has been done to enlarge the cross-section of the evacuation passage 11 in the area of the water seal and thereby increase its flow rate. On the other hand, the taper will have a very limited effect on the flow rate of the drainage passage since the reduction of the cross-section only extends over a short distance. The reference numeral 13 indicates a hole which ex¬ tends through the wall of the inner pipe 8. On the out¬ side of the pipe the hole 13 is hidden by a partition wall 14 indicated by dashed lines in Fig. 1, which at the top and along the sides is closely connected to the wall of the pipe but which is open at the bottom. In this way, a connecting conduit is formed between the drainage pas¬ sage and the evacuation passage, whose mouth in the drainage passage is located above the water level of the water seal while the mouth in the evacuation passage is located below the water level of the water seal. This ensures that the water seal is always kept filled because

water from the drainage passage can flow into the water seal.

In its upper end, the outer pipe 10 has a flanged portion 15 exhibiting an upper and a lower wall, between which the evacuation passage is delimited, while the eva¬ cuation openings 4 are located in the open sides of the flanged portion. When assembled, the lower wall of the flanged portion 15 will abut against the top surface of the floor and any water on the floor is allowed to flow in through the evacuation openings 4 in a horizontal direction between the upper and lower walls of the flang¬ ed portion and then in a downward direction around the inner pipe 8 and by the intermediary of the water seal into the waste pipe 3. Preferably, a seal (not shown in detail) is arranged between the lower wall of the flanged portion 15 and the floor surface as well as between the outer pipe and the waste pipe, as illustrated by an O-ring 16. Thereby, an unpleasant odour from the drainage system or from stag- nant water remaining between the flanged portion and the floor is avoided.

Referring now to Fig. 2, which shows a second embo¬ diment of an overflow according to the invention. This embodiment also comprises an inner pipe 8 and an outer pipe 10, but instead of a water seal only for the eva¬ cuation passage 11 there is a joint water seal for both the evacuation passage 11 and the drainage passage 9. The water seal comprises a cup-shaped member 25 which by the intermediary of a ring 16 and suspension means 17 is arranged on the outside of the outer pipe 10 by means of a thread connection between the ring and the outer pipe. The upper edge of the cup-shaped member 25 is located at a higher level than the outlet ends of both the inner and the outer pipe. This design is advantageous because a separate conduit connection does not have to be arranged between the drainage passage and the evacuation passage.

Fig. 3 shows a third embodiment of the invention. Like the first embodiment, this embodiment has a water seal for the evacuation passage only, but it is different from the first embodiment mainly in that the inner pipe 8 does not exhibit a taper but has a constant cross-section measurement along its whole length. This means that the evacuation passage in the area of the water seal has a smaller cross-section and consequently the flow rate of the passage is somewhat lower. On the other hand, this embodiment is somewhat easier to manufacture.

A fourth embodiment of the invention is shown in Fig. 4. This embodiment also has a water seal in the eva¬ cuation passage only, while the drainage passage extends without interruption from the inlet end to the outlet end. Furthermore, the outer pipe 10 is formed with a con¬ stant cross-sectional dimension and thus does not have a taper like the one in the embodiments described above. This is advantageous from the production point of view since it simplifies and reduces the cost of manufactur- ing. In order to ensure a snug fit between the lower waste pipe 3 and the upper part of the outer pipe 10 in spite of this absence of a taper, an annular fitting piece 18 is arranged around the outer pipe.

Also in the fifth embodiment according to Fig. 5, only the evacuation passage has a water seal, but its design is fundamentally different compared to the embo¬ diments according to Figs 1, 3 and 4, in that the water- retaining annular flange 12 is arranged on the inside of the outer pipe 10, while a shielding flange 19 extends from the inner pipe 8 with one flange portion 19' direct¬ ed outwards from the inner pipe and one flange portion 19" directed downwards, the lower edge of the flange portion 19" being located at a lower level than the upper edge of the flange portion 12". In the embodiment shown, the flange 19 is double-walled and the connecting conduit between the evacuation passage and the drainage passage is provided in the space between the walls in the flange.

Fig. 6 shows a sixth embodiment of the invention, in which the odour trap in the evacuation passage is mecha¬ nical. More specifically, the odour trap comprises a sleeve 20, which is displaceable along the inner pipe against the action of a spring 21. An outwardly extending portion 22 of the sleeve bridges the distance between the inner and the outer pipes, and in a closed position this portion abuts sealingly against the lower edge of the outer pipe. The upper part of the sleeve is located in an annular gap 23 around the inner pipe and abuts sealingly with its upper edge against the bottom of the gap in the closed position. When water flows down into the evacua¬ tion passage, the weight of the water will press the sleeve downwards, which will connect the evacuation pas- sage to the waste pipe.

Fig. 7 shows an application of the invention in a waste pipe from a sink in a sanitary room. The overflow in the Figure corresponds to the first embodiment accord¬ ing to Fig. 1 and is shown, for the sake of clarity, with the inner pipe 8 and the outer pipe 10 detached from each other. The reference numeral 24 indicates a connection piece, whose function it is to conceal the inlet openings of the evacuation passage, and the jacket wall of the connection piece exhibits holes or openings to enable the flowing of water into the evacuation passage. Preferably, the jacket wall has the form of a relatively close-meshed net in order to, at the same time, function as a strainer to prevent the penetration of waste material which could plug the water seal. Finally, Fig. 8 shows the invention in an applica¬ tion as an overflow for a dishwasher, a washing machine or a like installation. This application is primarily a possible choice for rooms which do not have a watertight floor covering, such as kitchens, where it is desirable to prevent an outflow of water from a leak onto the floor, which can penetrate into narrow openings in the floor covering or in underneath cupboards and the like.

A tub-shaped collecting vessel 26, of which only a por¬ tion is shown in the figure, is placed under the machine and is connected by the intermediary of a hose 27 to the inlet opening of the evacuation passage. In the event of a leak in the machine, the water will thus collect in the collecting vessel 26 and flow down into the waste pipe without causing any water damage to the building. Possible Modifications of the Invention

It is appreciated that the invention can be modi- fied in many ways within the scope of the appended claims. Although it is a preferred feature, which is shown in the drawings of all the preferred embodiments, it is, for example, not necessary for the overflow to be formed with a circular cross-section and consist of an inner and an outer pipe. Other cross-section shapes would be possible and the drainage passage and the evacuation passage could also be placed side by side e.g. as two semicircular pipes which are inserted into the lower waste pipe.