Patent Description:
In prior art connections assemblies, it is known to arrange a sealing ring having a circular cross-section between an outer pipe and an inner pipe connected to each other. This sealing ring, or O-ring, is conventionally positioned in a circumferential groove in the inner or outer pipe before the connection procedure and the inner pipe is then inserted into the outer pipe for forming a connection.

One drawback with these prior art connections is that the sealing ring may be displaced before or during the insertion of the inner ring, causing a faulty seal.

The document <CIT> discloses a pipe connection with a sealing ring which is designed as an air-cushion ring and is inserted into an encircling groove of the pipe socket, there being additionally provided a plurality of encircling chambers which are arranged between the external diameter of the spigot and the inner contour of the pipe socket and, in the active position of the pipe connection, are in partially asymetrical and partially symmetrical shapes of different volumes.

An object of the present invention is to provide a pipe connection assembly of the kind initially mentioned, wherein the risk of faulty seal is reduced.

The invention is based on the insight that the sealing ring may be provided with a cross-sectional shape different from circular.

According to a first aspect of the invention, there is provided a sealing ring for a pipe assembly according to claim <NUM>.

Furthermore there is provided a pipe assembly according to claim <NUM>.

In a preferred embodiment, the cylindrical wall comprises a spacing means in the form of a plurality of longitudinal ribs provided on the inner surface of the cylindrical wall. The longitudinal ribs are preferably concentrically provided and all have the same thickness.

In a preferred embodiment, an outermost portion of the cylindrical wall is formed as a curved flange of which the inner surface forms the circumferential groove.

In a preferred embodiment, the sealing ring has a cross-sectional shape further comprising a surface facing the groove and has a curvature that is adapted to a curvature of the curved flange of which the inner surface forms the circumferential groove.

In a preferred embodiment, in the cross-sectional shape, the slanting surface ends in a tip.

In a preferred embodiment, the plane surface faces away from the outermost end portion of the pipe.

In a preferred embodiment, the second angle is at least <NUM> degrees, preferably at least <NUM> degrees, even more preferably at least <NUM> degrees smaller than the first angle at some point of the abutment surface.

The pipe assembly according to any one of the preceding claims, wherein the first angle is between <NUM> degrees and <NUM> degrees, preferably between <NUM> and <NUM> degrees, and most preferably about <NUM> degrees.

According to a second aspect of the invention, a water trap is provided comprising an inlet portion and an outlet portion, wherein at least the outlet portion comprises a pipe assembly according to the invention.

In a preferred embodiment of the sealing ring, the second angle is at least <NUM> degrees, preferably at least <NUM> degrees, even more preferably at least <NUM> degrees smaller than the first angle at some point of the abutment surface (14e).

In a preferred embodiment of the sealing ring, the first angle is between <NUM> degrees and <NUM> degrees, preferably between <NUM> and <NUM> degrees, and most preferably about <NUM> degrees.

In the following, a detailed description of a pipe assembly according the invention, comprising a pipe and a sealing, will be given.

Turning first to <FIG>, a water trap in the form of a so-called bottle trap is shown, generally designated <NUM>. The water trap <NUM> comprises a vertical inlet portion <NUM> in the form of a pipe and a horizontal outlet portion <NUM> in the form of a pipe. The inlet portion <NUM> and outlet portion <NUM> have circular cross-sectional shape. The horizontal outlet portion <NUM> comprises a tubular pipe with a pipe wall having an outer surface and an inner surface.

A cup <NUM> is detachably attached to the lower end of the water trap <NUM>. The outlet portion <NUM> is adapted to be connected to a connection pipe <NUM>, see <FIG>, with an outer diameter adapted to allow a press fit between the outlet portion <NUM> and the connection pipe <NUM>, wherein the outlet portion <NUM> forms an outer pipe and the connection pipe forms an inner pipe in a pipe assembly.

Turning now to <FIG>, an end section of the outlet portion <NUM> is shown. A spacing means in the form of a plurality of longitudinal ribs <NUM> is provided on the inner surface of the wall 10a of the outlet portion <NUM>. From the sectional view shown in <FIG> it is evident that the pipe wall 10a has a uniform thickness and that the spacing means is concentrically provided on the inner surface. This means that all ribs have the same thickness, i.e., they extend the same distance towards the center axis of the outlet portion <NUM>.

A sealing ring <NUM> is provided in a circumferential groove 10c in the inner surface of the wall 10a constituting the outlet portion <NUM>. The sealing ring has a cross-sectional shape shown in <FIG> which is adapted for easy insertion of the connection pipe <NUM> according to <FIG>. To this end, the cross-sectional shape exhibits a slanting surface 14b which ends in a tip 14a when looking out of the outlet portion <NUM>. The sealing ring <NUM> has a plane P and the slanting surface 14b is at a first angle α to the plane P of the sealing ring <NUM>, see <FIG>. When determining this angle to the plane P, it is the angle between the plane P in the inner of the sealing ring <NUM> and the plane of the slanting surface 14b. In the shown embodiment, the first angle α is about <NUM> degrees, but it may vary between <NUM> degrees and <NUM> degrees, preferably between <NUM> and <NUM> degrees.

The surface 14c of the cross-sectional shape of the sealing ring <NUM> facing the groove 10c has a shape or curvature that is adapted to the curvature of the circumferential groove 10c. The surface 14d of the cross-sectional shape of the sealing ring <NUM> facing the ribs <NUM> is preferably planar.

Finally, an abutment surface 14e is formed between the surface 14d facing the ribs and the slanting surface 14b. The abutment surface 14e is designed to contact the outer surface of an inserted connection pipe <NUM>, see <FIG>. To this end, the abutment surface 14e has a surface being at a second angle β to the plane P that is smaller than the first angle α. Although in <FIG> there is a smooth transition from the slanting surface 14b to the abutment surface 14e, the second angle β must be substantially smaller than the first angle α at some point along the abutment surface 14e. In other words, the second angle β should preferably be at least <NUM> degrees, preferably at least <NUM> degrees, even more preferably at least <NUM> degrees smaller than the first angle α at some point of the abutment surface 14e.

By giving the abutment surface this angle, less material in the ring would have to be compressed during insertion of a connection pipe as compared to the case when an essentially planar slanting surface extends all way to the surface facing the ribs <NUM>.

In the embodiment shown in <FIG>, the abutment surface is curved, i.e., has a radius. This means that the angle β varies along this abutment surface 14e, from an angle essentially corresponding to the angle α to a smaller angle, in <FIG> approximately <NUM> degrees. This means that the material in the sealing ring <NUM> easily can be redistributed, making compression easier.

The abutment surface can take other shapes as long as they are covered by the wording of the claims. <FIG> shows an example not covered by the claims, where the angle of the slanting surface is the same as in the embodiment of <FIG>, while the abutment surface is at essentially right angle to the plane P of the sealing ring <NUM>.

Turning again to <FIG>, the outermost portion of the outlet portion <NUM> is formed as a curved flange 10b of which the inner surface forms the groove 10c. Thus, this groove 10c in which the sealing ring <NUM> is placed, together with the ribs <NUM>, delimit the movement of the sealing ring <NUM>, i.e., holds the sealing ring in place.

In <FIG>, it is shown how the circular end surface 20a, see <FIG>, of the connection pipe <NUM> facing the outlet portion <NUM> during insertion will slide on the slanting surface 14b, see <FIG>, when the outlet portion <NUM> and the connection pipe <NUM> begin to engage. Thanks to the slanting surface 14b of the sealing ring <NUM> which ends in a tip 14a, which is surrounded by the outer tip of the curved flange 10b, the insertion of the connection pipe <NUM> is facilitated. During further insertion, see <FIG>, the outer surface of the connection pipe <NUM> will continue to slide on the abutment surface 14e while slightly compressing the sealing ring <NUM> to ensure a tight fitting between the outlet portion <NUM> and the connection pipe <NUM>. Thanks to the shape of the slanting surface 14b, unintentional displacement of the sealing ring <NUM> is avoided. Thanks to the design with an abutment surface 14e having a surface being at a second angle β to the plane P that is smaller than the first angle α of the slanting surface 14b. , this connection pipe <NUM> will compress the sealing ring <NUM> to a limited degree. This is particularly useful when the sealing ring is manufactured from a material with a lower degree of flexibility than for example rubber, such as silicone. The stiffer nature of silicone also ensures that the sealing ring <NUM>, once placed in the groove 10c, will be difficult to remove.

In <FIG>, the connection pipe <NUM> with an outer diameter corresponding to the distance between diametrically opposite longitudinal ribs <NUM> is shown. This means that the connection pipe <NUM> during assembly is brought to slide into the inner of the outlet portion <NUM>.

In <FIG> an alternative connection pipe <NUM>' of a different standard is shown where the connection pipe <NUM>' has an inner diameter corresponding to the outer diameter of the outlet portion <NUM> and may thus be brought on the outside of the outlet portion <NUM>. This is facilitated by the distal end of the outlet portion <NUM> having a curved outer surface or flange. The alternative connection pipe <NUM>' is provided with a sealing ring <NUM>, preferably with a lip which in connected state is deflected and rests against the outer surface of the wall 10a of the outlet portion <NUM>. In this way, the flexibility of connecting to connection pipes of different standards is obtained.

<FIG> show the possibility of connecting the outlet portion <NUM> to connection pipes of different standards and thus different diameters. Thanks to the longitudinal ribs <NUM> which decrease the inner diameter of the outlet portion <NUM>, the wall 10a of the outlet portion <NUM> can be made with uniform but still small thickness, which from a manufacturing point of view is an advantage, since it is difficult to manufacture a tube with a large or non-uniform thickness. Also, the amount of material is kept down with this solution.

Embodiment of a pipe connection assembly according to the invention have been described. It will be appreciated that the principles thereof are applicable also to other applications than water traps. Thus, for example <FIG> shows a general design of a pipe assembly which may be used in any part of a piping system.

Also, although it is preferred to use the inventive concept of the sealing ring together with a pipe with internal longitudinal ribs, it will be appreciated that the claimed pipe assembly is not limited to this design but can also be used with pipes with smooth inner surface, as long as there is a circumferential groove therein.

Claim 1:
A sealing ring (<NUM>) for a pipe assembly having a cross-sectional shape comprising:
a plane surface (14d), defining a plane (P) of the sealing ring,
an essentially planar, slanting surface (14b) being at a first angle (α) to the plane (P) of the sealing ring (<NUM>), and
a groove surface (14c), interconnecting the plane surface (14d) and the slanting surface (14b),
the groove surface (14c) opposing the slanting surface (14b) and having a curvature such that it is connected to the slanting surface (14b), and
an abutment surface (14e) opposing the groove surface (14c) and interconnecting the slanting surface (14b) and the plane surface (14d),
characterized in that
the abutment surface (14e) comprises a curve defining the interconnection between the slanting surface (14b) and the plane surface (14d), wherein the angle of the abutment surface (14e) to the plane (P) varies along the abutment surface from the first angel (α) to a second angle (β) that is smaller than the first angle (α).