The invention is related to a tube connection for connection of smooth tubes to threaded tubes or threaded guide tube for i.e. water installations.

The fitting consists of a nut, elastomeric packing ring, support disc and retaining element, henceforward referred to as a retaining ring.

Fittings for connection of smooth tubes to threaded tubes or threaded guide tubes exist in many different constructions and types.

The problem in connection to this is the risk for leakage and the consequences connected to this. The purpose of this invention is to eliminate the risk for leakage optimally. Experiences for how leakage typically occurs are the basis for the development of the present model. It will be shown how an implementation of the new invention can solve the problem in a technical manner.

In one of the models an elastomer is used as a packing element between the threaded tube and the smooth tube, and this model has the disadvantage that the elastomeric packing ring that is placed inside the nut extending to the thread in the nut. This is necessary to ensure adequate surface of contact between the threaded tube and elastomeric packing ring in the instances where the threaded tube or threaded guide tube is provided with a chamfering which most are. The fact that the elastomeric packing ring extends to the thread lead to the fact that, when the elastomeric packing ring is compressed during tension, it risks becoming compressed in the thread with friction between the nut and the threaded tube as a consequence.

The person who tightens the fitting does not know whether the applied torque is used for overcoming friction or for safeguarding against extraction of the smooth tube. If the retaining ring has deformed the smooth tube and thereby retains it in correct position or not?

By compression the purpose is that the elastomeric packing ring shall cause pressure on the retaining ring, and this pressure will cause the retaining ring to fasten to the smooth tube - or expressed in another manner: Deforms the smooth tube. The design of the retaining ring is in such a way that the more pressure on this the stronger the retaining ring is tightened against the smooth tube to ensure better protection and adherence of this.

The consequence by friction between the nut and the threaded tube - where the elastomeric packing ring is compressed in the thread during tension, is that the retaining ring is not able to deform the smooth tube and therefore cannot secure it correctly.

Herewith the smooth tube risks becoming pushed out of the fitting due to the water pressure and water hammer that occur in water installations when taps are opened and closed.

With this, leakages and scenarios that occur with regard to extensive water damage can easily be imagined.

STATE OF THE ART- PRIOR ART

Models for this definite problem are only remotely represented through the patent literature.

The problem with leakage is, however, a known phenomenon in the patent literature, but when it comes to the elastomeric packing ring and an appurtenant recess inside the nut there is no known cited publication that this invention risks to infringe upon.

A few examples of inventions where the packing problem in fittings are the central subject.

US 2008/0061550 describe a (see figure 1-6) a fitting (20) for connection of smooth tubes (32, 36, 38) to threaded tubes or threaded guide tubes (30) where the fitting (20) consist of a nut (22), an elastomeric packing ring (26), a support disc (24) and a retaining ring (23) wherein the nut (22) is provided with an internal recess (40) and the same recess (40) is placed where the elastomeric packing ring (26), support disc (24) and retaining ring (23), and the elastomeric packing rings interior diameter is substantially less than the smooth tube's exterior diameter.

The present invention deviates from US 2008/0061550 in patent claim 1 by the fact that the recess roughly extends to the nut threads' maximum diameter and is executed with a sloping wall/chamfering that terminate the recess in the nut and by the fact that the elastomeric packing rings' width is adjusted to the width of the recess.

CA 1101458 is an example of a patent that touch lightly on the present problem. The elastomeric packing ring (gasket) is placed in a recess, but the recess is not placed in the nut but in the retaining ring and simultaneously the installation is related to the interior of a tube. Coincidentally the invention is specifically related to fittings for extremely large tubes.

US 4602792 specifically deal with the design of the elastomeric ring and have a completely different approach to the problem.

In US 5758910 the packing ring is made of metal and the fitting is aimed at gas couplings. Again, a completely different model.

US 4425095; this invention focuses on the material itself by, for example, the elastomeric ring and the design of each part and does not deal with a recess in the nut.

THE MEANS THAT ARE USED TO ACH EIVE THE SPECIFIC EFF ECT OF THE I NVE NTION

The invention is related to a fitting in which the nut is provided with a recess suitably spaced inside the nut and extending roughly outward to the nut threads maximum diameter. The width of the elastomeric packing ring roughly fits the recess in the nut.

More definite:

Fitting for connection of smooth tubes to threaded tubes or threaded guide tube, preferably in water installations where the fitting consists of a nut, elastomeric packing ring, support disc and retaining ring, characterized in the fact that the nut is provided with an internal recess that roughly extends to the nut threads maximum diameter and is executed with a sloping

wall/chamfering that terminates the recess in the nut. and in the same recess, wherein the elastomeric packing ring is placed inside the nut in the position that is given by, respectively, a support disc and retaining ring's extension in relation to the internal bottom of the nut, and the elastomeric packing ring's interior diameter is substantially less than the smooth tube's exterior diameter,

and moreover, the width of the elastomeric packing ring is adjusted to the width of the recess in the nut.

Elastomeric packing ring, support disc and retaining ring; these 3 elements are placed in the mentioned order and are situated above and under each other - the retaining ring is at the bottom of the nut. In the area where the elastomeric packing ring is above, respectively, the retaining ring and support disc, the recess is placed in the nut

PARTIULARS THAT ARE ACH IEVED IN RELATION TO THE STATE OF THE ART

When the elastomeric packing ring is compressed during tension it will not have the chance of being pinched between the thread in the nut and the threaded tube as the elastomeric packing ring is pushed away from outlet of the nut thread during compression.

The additional advantage is that the elastomeric packing ring is forced against the smooth tube during compression due to the sloped wall that terminates the recess in the nut. This condition contributes to optimizing of the tightness potential.

Another advantage is that the elastomeric packing ring is so well deposited in the nut that the interior diameter in the elastomeric packing ring can be less than the exterior diameter of the smooth tube, whereby a greater security is achieved concerning tightness as the elastomeric packing ring already during mounting is deformed in a radial direction without concerns that the elastomeric packing ring is pushed out of the nut when the fitting is pushed onto the smooth tube. One additional advantage is that the surface of contact against the elastomeric packing ring increases as a considerable part of the threaded tube/tube's "end" is placed against the elastomeric packing ring.

Herewith a construction is indicated that ensures that the applied torque to the nut is exclusively used for compression of the elastomeric packing ring as well as the retaining ring's deformation of the smooth tube. This increases the security for correct mounting and thereby less water damage.

Figures

Fig. 1 Nut according to the invention provided with a recess without compression

Fig. 2 with compression

Fig. 3 Traditional type without compression

Fig. 4 Traditional type where the embodiment involve friction

Fig. 5 Traditional type where the embodiment involve friction and minus deformation of the smooth tube

Numerical Reference

ut

lastomeric packing ring

upport disc

taining ring

readed tube or threaded guide tube

mooth tube

cess

hamfering/sloped wall

Examples of design

Fig. 1 and fig. 2 both illustrate the invention and the functionality of the invention, while fig. 3-5 illustrate the known technology as well as the disadvantage of the same. Fig. 1 illustrates the nut (1) with a recess (7) where the elastomeric packing ring (2) is placed in the recess (7) and the elastomeric packing ring (2) is not under compression.

Fig. 2. illustrates the same as fig. 1 but now the elastomeric packing ring (2 ) is under compression which transmits to the retaining ring (4). This (4) is in tension with the smooth tube (6) - in the technical language it is expressed in such a way that the retaining ring (4) deforms the smooth tube (6).

Fig. 3 illustrates prior art where the elastomeric packing ring placed inside the nut extends to the thread in the nut.

And where the elastomeric packing ring is not under compression.

Fig. 4 shows the elastomeric packing ring compressed in the thread

Fig. 5 shows the elastomeric packing ring compressed in the thread with friction between the nut and the threaded tube as a result, and where it is seen that the retaining ring has not deformed the smooth tube and thereby not secured it correctly. Herewith the smooth tube risks becoming pushed out of the fitting due to the water pressure and the water hammer that occur in water installations when taps are opened and closed.