GB2125504A - Hose fitting - Google Patents

Abstract

A fitting for a hose with reinforcement layers incorporated in the hose material, comprises a metal nipple (2) having at least one bearing sleeve (4, 8) to which reinforcement layers (5) are fixed. The reinforcement layers (5) in the entire area of the bearing sleeve (4, 8) are embedded in rubber or rubber-like material (6) of high strength and low extensibility, the embedding material being firmly connected to the bearing sleeve. The embedding material is preferably hard rubber. <IMAGE>

Description

SPECIFICATION Hose fitting The invention relates to a hose fitting for connecting a hose to other pipe systems, for connecting two hose ends or for closing a hose end, particularly for use with high-pressure hoses with large diameter, with reinforcement layers incorporated into the hose material, consisting in a metal nipple with at least one bearing sleeve, to which the reinforcement layers are fixed.

For example, in the field of progressively expanding oil drilling in offshore situations, the demands which are made in particular of flexible hoses for the transport of petroleum and natural gas, with higher working pressures and greater nominal widths being required, are especially on the increase. With such hose systems, connection technology is critical in this area of demand.

It is already known to provide the connection nipples, made of metal, and designed in the manner of a sleeve in the area connected with the end of the hose, be it as inner sleeve or as outer sleeve, with a series of steps, there being provided for each reinforcement layer of the hose construction a separate step to which the corresponding reinforcement layer or group of reinforcement layers is secured.

The areas of application of the individual reinforcement layers on the adhesion sirface of the metal nipple lie in this arrangement staggered with respect to one another in an axial direction, so that the thread tension introduced into the hose material at the end of the metal nipple differs from layer to layer.

The tension distribution, irregular from hose to nipple in this transitional area in the individual layers, originates from the fact that the individual reinforcement layers which are fixed at places of the sleeve axially staggered one in respect to the other, are correspondingly able to expand in varying degrees. An uneven distribution of tension is disadvantageous insofar as thereby the individual strength bearers of the material are no longer optimally used and thereby a reduction of the internal pressure resistance of the hose occurs in this area.

The invention has for its object to develop further a hose fitting of the type first defined hereinabove in such a manner that the strength of the hose construction in the fitting area is not reduce#d, and in particular the internal pressure resistance is not lowered.

This object is achieved according to the invention in that the reinforcement layers in the entire area of the bearing sleeve are embedded in rubber or rubber-like material with high strength and small extensibility, and in that the embedding material is firmly connected with the bearing sleeve. The reinforcement layers embedded in the rubber-like material with high strength and small extensibility are fixed almost immovably in the material.

Differing elongations from layer to layer cannot therefore occur any longer in the area of the nipple, so that the reinforcement layers at the end of the nipple, where the layers go over from the embedding material into the hose wall consisting of elastic rubber, exhibit an almost constant state of tension. There is effected by this behaviour of the reinforcement layers an even optimum utilization of all the strength bearers provided. This applies both to nipples with inner sleeves and to those with outer sleeves. On the basis of the fact that the reinforcement layers in the entire area of the bearing sleeve are embedded firmly and non-elastically, the constructional length of the nipple can be considerably reduced as compared with the known versions, so that a ducting section equipped with the fitting according to the invention exhibits a relatively short rigid fitting section.The good flexibility of a hose is therefore not substantially adversely affected by the fitting.

Preferably, the embedding material which surrounds the reinforcement layers to be fixed is of hard rubber which has a high E modulus and a comparatively high strength. In addition, hard rubber is easy to process during the making of the hose, and, in particular, it is possible to achieve a good transition to the elastic rubber of the hose material.

For the improvement of the properties demanded here the hard rubber can contain reinforcing material, and, preferably, fibrous material with high tensile strength, such as, for example, glass fibres or carbon fibres.

The fixing of the embedding material to the bearing sleeve may preferably be effected via a metal/rubber connection.

On the basis of the concept according to the invention, the metal nipple may be provided with an inner sleeve for the most diverse instances of application of the hose, without the known drawbacks, such as the non-utilization of the entire construction of the reinforcement layers, occurring. In addition, on using inner sleeves, the advantage of the easier manufacturing process is exploited. The application of external shells which have to be placed subsequently on the hose end makes said process considerably more difficult.

Finally, the inner sleeve has also advantages with hoses stressed as they are pulled longitudinally, as the hose then is constricted and therefore the seating on the sleeve is further improved.

If an inner sleeve is used as bearing sleeve, the embedding material for the reinforcement layers may also be connected with the bearing sleeve by shrink fit.

In that area in which the bearing sleeve is connected with the embedding material for the reinforcement layers it can have a constant diameter. The latter is suitably profiled so that adhesion between bearing sleeve and embedding material is improved. The profiling selected may be, e.g. that of a screw thread, which is very easy to apply.

The bearing sleeve may also be constructed in stepped fashion in the manner known per se, the series of steps lying inside or outside.

Each reinforcement layer or each group of reinforcement layers then extends in each case as far as one of the steps. The individual reinforcement layers then cover the bearing sleeve along a different length, but the inelastic embedding of the reinforcement layers effects that no different elongations in the individual reinforcement lengths relatively to one another can take place, and therefore also with this construction even tension conditions at the nipple end prevail in all reinforcement layers.

The invention is illustrated for the sake of example in the drawing, and described in detail hereinunder on the basis of the drawing in which: Figure 1 is a section through a fitting with an inner sleeve which, in its adhesion area, has a constant diameter; Figure 2 is a cut-out section from Fig. 1 in magnified representation with a modified surface form of the bearing sleeve, and Figure 3 is a section through a fitting with a stepped bearing sleeve.

In Fig. 1 of the drawing there is represented a section through a hose end 1 which is connected to a metal nipple 2. The metal nipple 2 has a connecting flange 3 by which the hose end is connected to another hose end, or may be joined to any desired pipe system, as well as a bearing sleeve 4 to which the hose end 1 is secured.

Hose 1 is made of elastic rubber and in the embodiment shown in the drawing has six reinforcement layers 5. In the area around the bearing sleeve 4 the reinforcement layers 5 are embedded in hard rubber 6, which, for its part rests firmly through a metal/rubber connection on the bearing sleeve. In the end area 7 of the bearing sleeve the hard rubber 6 merges with elastic hose rubber.

The sleeve 4, in the area in which it is used to support the layer of hard rubber 6 as well as the reinforcement layers 5, has a fairly constant diameter. The reinforcement layers which lie in the area around the sleeve 4 are of substantially the same length. The reinforcement layers 5 are firmly inserted in the hard rubber layer 6, so that in the transitional area 7, in which they merge with the more elastic hose rubber, they exhibit substantially equal tension conditions, which guarantees good strength properties. The good strength properties are, in particular, achieved by optional use of all the strength bearers present in the hose.

In the embodiment shown in Fig. 2, the external surface which carries the hard rubber layer 6 with the embedded reinforcement layers 5, is shaped like a screw thread 10, so that adherence between the hard rubber 6 and the sleeve 4 is further improved.

In the embodiment shown in Fig. 3, in which identical parts are denoted by identical reference numbers, metal nipple 2 has a stepped bearing sleeve 8. This is provided on its external surface with three steps 9 with which in each case two of the six reinforcement layers 5 are associated.

In the entire area around the bearing sleeve 8 the reinforcement layers 5 are embedded in hard rubber 6 which is secured to the stepped sleeve 8 by means of a metal/rubber connection. The hard rubber layer 6 extends right into the transitional area 7 at the end of the sleeve 8, where the reinforcement layers 5 merge into the elastic rubber of the hose 1.

Also in the embodiment of Fig. 3 the reinforcement layers 5 are solidly inserted over their entire length into the hard rubber layer 6, so that, in spite of their differing lengths, they still have the same conditions of tension in the transitional area 7.

Claims (12)

1. A fitting for connecting a hose to other pipe systems, for connecting two hose ends together or for closing a hose end, particularly for use with high-pressure hoses of large diameter, with reinforcement layers incorporated in the hose material, comprising a metal nipple provided with at least one bearing sleeve, to which the reinforcement layers are fixed, characterised in that the reinforcement layers in the entire area around the bearing sleeve are embedded in rubber or rubber-like material of high resistance and small extensibility, and in that the embedding material is firmly connected to the bearing sleeve.

2. A hose fitting according to Claim 1, characterised in that the embedding material is hard-rubber.

3. A hose fitting according to Claim 2, characterised in that the hard rubber contains reinforcing material.

4. A hose fitting according to Claim 3, characterised in that the reinforcing material in the hard rubber is fibrous material of high tensile strength.

5. A hose fitting according to any one of Claims 1 to 4, characterised in that the embedding material for the reinforcement layers is fixed to the bearing sleeve by means of a metal-rubber connection.

6. A hose fitting according to any one of Claims 1 to 5, characterised in that the bearing sleeve is an inner sleeve.

7. A hose fitting according to Claim 6, characterised in that whe embedding material for the reinforcement layers is a shrink fit on the bearing sleeve.

8. A hose fitting according to any one of Claims 1 to 7, cliaracterised in thaw the L~ > ,- ing sleeve is of substantially constant diameter in the area in which it is connected to the embedding material for the reinforcement layers.

9. A hose fitting according to any one of Claims 1 to 8, characterised in that the bearing sleeve is profiled in its adhesion area.

10. A hose fitting according to Claim 9, characterised in that the profile is that of a screw thread.

11. A hose fitting according to Claim 1, characterised in that the bearing sleeve is stepped in its adhesion area and in that each reinforcement layer or each group of reinforcement layers extends in each case as far as the associated step.

12. A hose fitting substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2 or Fig. 3 of the accompanying drawing.