GB2372788A - Hose with swaged coupling member - Google Patents

Abstract

A hose, which may comprise resilient inner and outer layers 2a, 2b, with a layer of reinforcement 7 in between, has a metal coupling member swaged on to one end. The coupling member comprises an annular socket 1 at one end into which the hose is inserted, and connection means at the other end. The socket has inwardly directed circumferential ribs 6 on its outer wall, and outwardly directed circumferential ribs 4 on its inner wall. The outwardly directed ribs may be shaped in cross-section as teeth directed away from the mouth of the socket, where the teeth become progressively sharper along the length of the socket away from the entrance. Preferably the ribs on at least one of the walls are shaped so that during swaging, material of the resilient surface of the hose is displaced by the ribs into the spaces between the ribs without compression of the material of the hose.

Description

HOSE OR PIPE HAVING COUPLING THEREON Field of the Invention This invention relates to hoses or pipes, and in particular to high pressure hoses or pipes having swaged metal couplings thereon.

Background to the Invention High pressure flexible hoses typically consist of a reinforcing core of fibres or wires encased in a resilient material such as rubber or plastics. To form connections between hoses or to connect the hose to a valve or other termination, it is conventional to swage on to the end of the hose a metal coupling. The coupling is typically formed with an annular socket into which the hose end is inserted, the coupling then passing through one or more swaging dies to compress the walls of the socket into engagement with the hose wall to form a fluid-tight connection. The inner walls of the socket may be provided with annular ribs which bite into the resilient material to improve the connection. Such hoses are typically used in the oil industry, for example for hoses associated with oil drilling and production rigs, and for tanker connections.

Summary of the Invention According to one aspect of the invention, there is provided a hose or pipe having resilient inner and outer surfaces, and a metal coupling member swaged on to an end thereof, the coupling member comprising, before swaging, an annular socket opening at one end thereof into which the hose or pipe end is inserted, and connection means at the other end thereof, the socket having inwardly-directed circumferential ribs on the outer wall thereof and outwardly-directed circumferential ribs on the inner wall thereof, wherein the outwardly-directed circumferential ribs are shaped in longitudinal cross-section as teeth directed away from the entrance to the socket, and wherein the teeth become progressively sharper along the length of the socket away from the entrance.

Thus, the ribs or teeth adjacent to the entrance are more rounded in profile than those remote from the entrance. It has been found that the use of this configuration substantially increases the pressure at which failure of the connection to the cou

pliny occurs ; failure of the hose remote from the coupling has been found to be more likely.

The inwardly-directed ribs on the outer wall of the socket are also preferably shaped in longitudinal cross-section as teeth directed away from the entrance to the socket, and the teeth may also become progressively sharper along the length of the socket away from the entrance.

According to another aspect of the invention, there is provided a hose or pipe having resilient inner and outer surfaces, and a metal coupling member swaged on to an end thereof, the coupling member comprising, before swaging, an annular socket opening at one end thereof into which the hose or pipe end is inserted, and connection means at the other end thereof, the socket having inwardly-directed circumferential ribs on the outer wall thereof and outwardly-directed circumferential ribs on the inner wall thereof, wherein the ribs on at least one of the walls of the socket are shaped such that, during swaging, material of the resilient surface of the hose or pipe is displaced by the ribs into the spaces between the ribs substantially without compression of the material.

Preferably, the ribs are shaped so that the material of the hose or pipe flows into the spaces behind the teeth, relative to the direction thereof, so as to fill the spaces.

More preferably, the teeth do not penetrate to engage the reinforcing material in the hose or pipe. Preferably, at least the inner ribs are shaped in this manner, but the outer ribs may also, or alternatively, be so shaped.

The hose or pipe is typically of the type having a layer of reinforcement material encased between inner and outer layers of resilient material, for example a thermoplastics material such as polyethylene or polypropylene, or an elastomer such as a synthetic rubber. The reinforcement may be in the form of ceramic fibres, polymer fibres such as those sold under the Registered Trade Mark KEVLAR, glass fibres, carbon fibres, metal wires, or metal tapes.

The metal coupling is suitably formed from steel, for example carbon steel or stainless steel, and conveniently comprises inner and outer tubular parts welded together to form the socket between them. The free end of the coupling may be provided with an external or internal screw-thread, a flange, or any other means of con

necting the coupling to another fitting or valve, or to another such hose. For example, the coupling may be provided with a surface adapted to be welded to another fitting.

The invention is not limited to the use of couplings having one particular type of connection.

It will be understood that hoses are generally relatively more flexible and pipes relatively less flexible, but a clear dividing line between the two is difficult to define; however, references herein to"pipe"assume some degree of flexibility, and in particular some resilience of the surfaces thereof. References hereinafter to "hose" will therefore encompass"pipe".

Brief Description of the Drawings In the drawings, which illustrate an exemplary embodiment of the invention: Figure 1 is a partial cross-sectional view of a coupling before swaging, with the hose end inserted; Figure 2 is a partial cross-sectional view of the inner part of the coupling of Figure 1 ; Figure 3 is an enlarged sectional view of the ribs of the component shown in Figure 2; Figure 4 is a view corresponding to Figure 1, showing the start of the first stage of the swaging process; and Figure 5 is a similar view to that in Figure 4, but illustrating the configuration before commencement of the final stage of the swaging process.

Detailed Description of the Illustrated Embodiment Referring first to Figures 1 to 3, the unswaged coupling comprises two components which are welded together to define between them a socket 1 into which the hose end 2 is inserted. The inner component 3 has at one end an externally screwthreaded connection and at the other a section of reduced diameter having external circumferential ribs 4 evenly spaced therealong. Each rib 4 is shaped in cross-section like a tooth directed away from the entrance to the socket 1, with the teeth becoming progressively sharper or more pointed away from the entrance as may be seen from Figure 3. The first rib 4a nearest to the entrance to the socket has a relatively rounded

profile, while the last rib 4j furthest from the entrance has a sharp toothed profile. It will also be seen that the diameters of the peaks of the ribs increase slightly along the length of the coupling, so that the first rib 4a also has the smallest diameter. while the last rib 4j has the greatest diameter. This ensures that, after swaging, the inward force exerted on the hose by the coupling increases progressively away from the entrance to the socket, thereby reducing the sharp transition between the swaged and free portions of the hose.

The ribs 4 are also dimensioned such that the spaces between them are substantial equal in volume to that of the ribs, whereby material displaced by each rib from the inner surface of the hose during swaging can flow into the spaces between the ribs substantially to fill the space without significant compression of the material. It has been found that this configuration significantly increases the strength of the connection between the coupling and the hose, thereby increasing the resistance of the connection to fluid pressure within the hose In use.

The outer component 5 of the coupling has circumferential ribs 6 which are inwardly directed within the socket 1, and are also shaped so that the spaces between the ribs are substantially equal in volume to that of the adjacent ribs. Again, in profile the ribs 6 show a toothed configuration with the teeth angled away from the entrance to the socket 1.

The hose 2 is suitably of the type having one or more reinforcing layers 7 between layers of elastomeric or thermoplastic material. The reinforcing material 7 may be metal tapes wound in opposite directions so as to overlap, or metal wires or ceramic or other fibres braided or otherwise provided within the hose wall.

The coupling comprises two tubular components which can conveniently be formed from steel tube, machined internally and externally to provide the desired profile. The two components are then welded together to provide the structure illustrated in Figure 1. The inner tube 3 could be initially formed by forging, although machining would still be necessary to provide the external ribs, or at least to finish the ribs to the desired profiles. The outer tube 5 may possibly be manufactured by deforming a thinner tube, as opposed to machining of a relatively thick-walled tube. A range of different

outer components of different inner diameters may be required to accommodate variations in the dimensions of the hose, for example hoses with different wall thicknesses for different operating pressures, or to compensate for manufacturing tolerances. It may also be necessary to provide couplings having different inner component diameters where variations in internal diameter of the hose require this.

A hole 8 is provided through the outer component of the coupling, at the end thereof remote from the entrance. This serves to allow escape of air from the socket during swaging, as hereinafter described. To prevent ingress of moisture in use, the hole will need to be sealed. It may be possible to position the hole such that the displacement of the hose in the socket due to the swaging action will block the hole at the completion of swaging.

In an alternative arrangement, venting means may be provided in place the simple hole, to allow escape of gases, but to prevent ingress of moisture or air. This may be desirable if permeation of gas or liquid from within the tube then enters the reinforcing layer. Allowing this gas or liquid to vent from the end of the hose will serve to prevent pressure build-up within the hose wall, possibly leading to delamination. A further possibility would be the addition of a pressure detector at the vent (or in place of it) to provide a warning of pressure increases which may be due to leakage within the hose.

Referring now to Figures 4 and 5, the assembly of the coupling with the hose comprises three main steps: insertion of the hose end 2 into the socket in the correctlysized coupling ; internally swaging the inner part 3 of the coupling into engagement with the inner surface of the hose; and then externally swaging the outer part 5 of the cou pling into engagement with the external surface of the hose. The dimensions of the coupling are ideally selected such that the hose is a sliding fit within the socket. However, to accommodate variations in the external dimensions of the hose resulting from normal manufacturing tolerances, it may be preferred to use a standard coupling dimensioned to accommodate hose within the tolerance range, and selecting different swaging dies according to the actual internal and external diameters of the hose.

The coupling is first mounted over a shaft 10 of a ram (not shown) which passes through an abutment plate 11 against which the end of the coupling rests. The swaging tool 12 is then screw-threaded on to the shaft so as to come to rest against the end of the inner part of the coupling (if necessary, the shaft is adjusted in position to bring the tool into contact with the coupling, as shown in Figure 4. The hose is then inserted into the socket over the tool 12 until a pre-marked length is within the socket. The ram is then operated to pull the tool 12 through the coupling until the internal clearance of the threaded portion of the coupling permits the coupling to be removed from the tool 12.

The final step of the method is illustrated in Figure 5. A two-part swaging die 13 is positioned around the hose and with its wider entrance part receiving the socket end of the coupling. A pushing ram (not shown) has a cup 14 at the end thereof into which the threaded end of the coupling is located. The ram is then extended to push the coupling through the swaging die 13. swaging the outer part 5 of the coupling into contact with the outer surface of the hose.

Claims (10)

1. CLAIMS 1. A hose having resilient inner and outer surfaces with reinforcement therebetween and a metal coupling member swaged on to an end thereof, the coupling member comprising, before swaging, an annular socket opening at one end thereof into which the hose end is inserted, and connection means at the other end thereof, the socket having inwardly-directed circumferential ribs on the outer wall thereof and outwardly-directed circumferential ribs on the inner wall thereof, wherein the outwardlydirected circumferential ribs are shaped in longitudinal cross-section as teeth directed away from the entrance to the socket, and wherein the teeth become progressively sharper along the length of the socket away from the entrance.
2. 2. A hose according to Claim 1, wherein the inwardly-directed ribs on the outer wall of the socket are also shaped in longitudinal cross-section as teeth directed away from the entrance to the socket
3. 3. A hose according to Claim 2, wherein the teeth also become progressively sharper along the length of the socket away from the entrance.
4. 4. A hose having resilient inner and outer surfaces with reinforcement therebetween and a metal coupling member swaged on to an end thereof, the coupling member comprising, before swaging, an annular socket opening at one end thereof into which the hose end is inserted, and connection means at the other end thereof, the socket having inwardly-directed circumferential ribs on the outer wall thereof and outwardly-directed circumferential ribs on the inner wall thereof, wherein the ribs on at least one of the walls of the socket are shaped such that, during swaging, material of the resilient surface of the hose is displaced by the ribs into the spaces between the ribs substantially without compression of the material.
5. 5. A hose according to Claim 4, wherein the ribs are shaped so that the material of the hose flows into the spaces behind the teeth, relative to the direction thereof, so as to fill the spaces.
6. 6. A hose according to Claim 5, wherein at least the inner ribs are so shaped.
7. 7. A hose according to Claim 4, 5 or 6, wherein the teeth do not penetrate to engage the reinforcing material in the hose.
8. 8. A hose according to any preceding claim, wherein the socket is so shaped an dimensioned that, after swaging on to the hose, the force exerted by the coupling on the hose increases progressively along the socket away from the entrance thereto.
9. 9. A hose according to any preceding claim, formed of a thermoplastic or elastomeric material encasing the reinforcing material.
10. 10. A hose according to any preceding claim, wherein the reinforcing material is a fibrous material.