GB1575355A - Hose - Google Patents

Description

(54) IMPROVED HOSE (71) We, TAURUS GUMIIPARI VALLALAT of 1087 Budapest, Kerepesi ut 17., Hungary, a body corporate organized under the laws of Hungary, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The invention concerns a hose intended to be exposed to and capable of withstanding the combined effect of simultaneously acting stress forces of internal and/or external pressure or vacuum and axial tensile and/or torsional loads.

There are known rubber hoses of special type produced by conventional technology and capable of withstanding the effect of internal pressures or vacuum and small external pressures and/or tensile stresses.

Such rubber hoses are often constructed of internal stiffeners that are helically wound with a small pitch-angle and of at least one but usually more cores placed above or under the stiffeners; the core(s) being made of a textile, cord or a metal filament or cable, dimensioned to produce the required rigidity to withstand the internal pressure applied. The material of the stiffeners is usually a metal, i.e. a steel wire of circular or rectangular cross-section, and it plays an important role when vacuum or an external pressure is applied.

With the accelerating progress of technical development, increasingly a demand arises for hoses capable of bearing very large combined stress loads, such as high external pressure, tensile load, torque and vacuum which in many cases act simultaneously. Such hoses are required e.g. for deep-sea drilling, as well as for supply pipe lines, flexible deep-sea conduits or cables, flexible boring bars and for flexible pipe line systems for pile-driving hammers.

The above-described hoses are not suitable for bearing very large stress loads, due to the fact that winding the steel wire stiffener at a low pitch angle is very difficult when a certain limit in the cross-section of the wire is exceeded. The coiling of a solid metal wire of large cross-section, which would be necessary to bear the applied stress loads in use, cannot be achieved. This sets an upper limit on the load/stressbearing capability and also on the diameter of the hose. A further drawback of steel spiral wire is that steel has a low limit of elastic deformation as a result of which small circumferential deformations can cause permanent deformations of the shape of the hose.

French Patent Specification No. 2 182 372 (= BP 1 423 059) describes a hose construction, and its manufacture, which is said to be able to bear high stress loads. This construction is, however, entirely different from the customary design and traditional process of manufacture of hoses. Such hose comprises one or more reinforcing core(s) of steel wire with specially shaped cross-sections. These cores consist of wires of S-shaped or Zshaped profiles, linked together. The flexibility of the hose is achieved by the movement within each other of the interlinked profiled metal elements and by the provision of an elastomeric or plastics layer interposed between the outer surfaces of the profiled elements. The drawbacks of this construction are the heavy weight of the cores and that the parts made of metal and resilient materials are not bound together and thus under stress they do not behave as a uniform homogeneous constructional unit.

As a result, the hose becomes rigid under internal pressure and separation of the surfaces develops in use or even in the course of the manufacture of the hose itself; the profiled elements are displaced, they pinch and crumble the elastomeric layer embedded between them, or when the hose is twisted, the linked profiled wires open up.

The locations of the hose where these undesirable effects manifest themselves become increasingly exposed to the effects of corrosion, wear and tear and to other life-shortening effects and can cause trouble in the practical use of the hose. A complete separation of the linkage of the profiled wires can cause the hose to burst.

It is also known that glass fibre reinforcement may advantageously be used for hose construction particularly where the hose has to bear tensile and bending stress forces.

In practice, several attempts have been made for using laminated glass reinforcement in hoses. Such constructions can however, be used only in the case of small stress loads, mainly in the case of plastics hoses. Such constructions are described e.g.

in the British Patent Specification No. 1197 595. The essence of this construction is that it contains extruded strips, hollow bodies and glass fibre reinforcement placed inside the cavity of the hollow bodies as constructional elements of the hose. The final shaping of the product is carried out immediately after extrusion, by hot-pressing, optionally combined with additional heating, to achieve fusion.

The glass fibres are in form of parallel untwisted tows thus rendering the core of the hose rigid. When a helical core of large cross-section is bent, then due to the difference in the length of the "thread" varying pre-tensions and "crinkles" are generated in the fibres.

It is known from German published patent application No. 2513831 (= B.P.A. No.

11689/75, Serial No. 1488975) to provide a hose capable of bearing high internal and/or external pressures, which has a core made of stiffening rings formed by densely packed mutually parallel resin glass-fibres. According to this prior invention, the use of a spiral consisting of resin-glass fibres is considered positively detrimental.

However, the construction described in this prior publication i.e. the manufacture of the structural elements of the resin-glass fibre and their fitting onto the hose makes the production technology of the hose cumbersome and complicated and the production itself cannot be carried out by the conventional methods and equipments of hose manufacture.

It must be considered as another disadvantage of this design that such a hose is not suitable for bearing various large complex loads e.g. simultaneously acting external and internal pressures, tensile and torsional stresses.

As a further drawback, regard must be had to the fact that the rings consist of densely packed resin-glass fibres laid sideby-side, and due to the radial-type hose design, the hose becomes too rigid i.e. is difficult to bend.

We have discovered a process consisting of a combination of per se known technological operations, which does not require any deviation from the customary production process of the rubber industry or expensive new plants, and which leads to the production of a new product which eliminates or reduces the drawbacks originating from the requirements imposed by the present state of the art and meets current demands.

According to the invention this process is based on the discovery that it is possible to produce a hose capable of bearing extraordinary large stress loads which satisfies all requirements even of special applications and which can be manufactured by combining the different phases of the usual production process of the rubber industry. By using this method, it is possible to produce a core helix of fibre and resin and of large crosssection because, when the helical line is made, the resin is still soft and the winding of the helix does not require a large bending force as would be necessary when using a profiled steel wire of identical cross-section.

The word "hose" as used herein, including the patent claims, is not restricted to a product performing the customary (conveying) functions of a hose but covers all design and structural elements used in other domains of industry where their function is to bear the mentioned large stress loads and its design and construction makes its application possible.

According to the invention there is provided a cylindrical hose suitable for withstanding any one of a combination of internal and/or external pressures or vacuum, a tensile load and a torsional load, comprising a plurality of adjoining layers which taken in a radially outward direction include: a first layer comprising a helical core of fibre and resin material wholly or partially embedded in a rubber jacket, the helical core having an elongated cross-sectional shape with a length, in a direction parallel to the central longitudinal axis of the hose, greater than a width, in the direction perpendicular to said central longitudinal axis, in the ratio of at least 1.4 to 1, the helical core and the rubber jacket being simultaneously formed into a space lattice, a second layer which comprises a ply of fabric material for stress distribution, a third layer of rubber which serves as a cushion layer to provide flexibility, a fourth layer which comprises reinforcing stiffeners encircling the longitudinal axis of the hose, a fifth layer which comprises a ply of fabric material, and a sixth layer which comprises an outer protective rubber covering.

Preferably the fibre and resin material is wholly embedded in the rubber jacket and the first layer is covered on its radially inner surface by an internal rubber layer the radially inner surface of which defines the flow-confining wall of the hose, the fibre and resin material being bonded to the rubber jacket to form said first layer simultaneously with bonding of the rubber jacket to the internal rubber layer.

The invention is described, purely by way of example, with reference to preferred embodiments illustrated in the accompanying drawings. To simplify the description, we refer, instead of fibre-reinforced synthetic resin, to a resin-glass fibre arrangement used as an internal helix, but the invention is not limited to this preferred embodiment which is described purely as an example.

Thus other types of reinforcing fibres, mentioned above, may also be used instead of glass fibre.

In the drawings: Figure 1 shows a longitudinal section of a first embodiment of a hose according to the invention, Figures 2 and 3 illustrate in longitudinal section two further embodiments of a hose according to the invention Figures 4 and 5 show a cross-section of a helical core or insert consisting of an arrangement of resin and glass fibre, Figure 6 illustrates another embodiment of a hose according to the invention in longitudinal cross-section Figure 7 shows a cross-section of part of the hose of Figure 6, with the helix consisting of an arrangement of resin and glass fibre, and Figure 8 shows the same cross-section of the helix but with an electrically conducting metal filament embedded therein.

Referring to the drawings, a cylindrical hose shown in Figure 1 has an internal rubber layer 1 which is cross-linked with a rubber coating 2 which surrounds a helical core 3 made of an arrangement of resin and glass fibre (optionally stranded glass fibre).

The hose is fitted with reinforcing stiffeners or cords 7 and 8 encircling the longitudinal axis of the hose and a fabric reinforcement ply 5 for stress distribution. The hose is protected against mechanical and chemical effects by an outer skin layer 10 surrounding a ply 9 of fabric reinforcement. A cushion layer 6 of rubber is located between the fabric reinforcement ply 5 and the reinforcing cords 7 and 8, beneath the latter. In Figure 1, and in subsequent embodiments to be described, the core 3 and the coating 2 are simultaneously formed into a space lattice, i.e. into their three dimensional configuration.

The hose shown in Figure 2 differs from the hose illustrated in Figure 1 in that it has an internal rubber layer 1, its innermost flow-confining layer being formed by the rubber coating 2 of the helical core 3, consisting of resin and glass fibre, facing the interior of the hose.

Figure 3 illustrates the structure of a preferred hose according to the invention where the core 3 consisting of resin and glass fibre, is only partly embedded in rubber coating 2, instead of being wholly embedded in the coating 2 as in the Figures 1 and 2.

The cross-section of the core 3 consisting of resin and glass fibre, and illustrated in Figure 3 is shown in Figure 4.

Figure 5 shows core 3 with a built-in electrical conductor metal filament 3a.

The sealing ability (or impermeability) of the hose illustrated in Figure 6 is ensured by the internal rubber layer 1 which is chosen so that, by virtue of its chemical and physical properties, it should meet the requirements regarding the liquid to be conveyed by the hose. The internal rubber layer 1 forms an inseparably cross-linked unit with the helically wound rubber coating 2 enclosing the embedded core 3 consisting of resin and glass fibre. The helix of stiffening core 3, made of resin and glass fibre, and rubber coating 2 has 1-3 turn start(s) and a spacer layer 4 is interposed between the turns of the helix. For a plurality of turn starts, there are thus a plurality of cores 3 which are angularly displaced or interlaced around the longitudinal axis of the house. Using this layer 4, the distance t between two adjacent turns of the core 3, consisting of resin and glass fibre, can be selected at will; the distances a and b as shown illustrate the dimensions of the core in two orthogonal directions.

The international pressure prevailing in the hose is transferred partly to the core 3 and partly via the space t to the reinforcing cords 7 and 8. The equalisation of the acting forces is performed by the fabric reinforcement 5 which transfers the compression forces directly or via cushion layer 6 to the reinforcing cords 7 and 8.

The hose is protected against mechanical and chemical effects by cover layer 10 adjoining fabric reinforcement 9.

Figure 8 shows a helical core, consisting of resin and glass fibre, and provided with an electrically conducting metal filament 3a, whereby to make the hose suitable for conducting electricity, by ensuring a metallic connection between adjacent hoses, including couplings.

When the hose is subjected to tensile and/or torsional forces a radially inwardly directed distributive stress load is transferred from the reinforcing cords 7 and 8 via the cushion layer 6 and through the top layer of the rubber coating 2 to the helically wound core 3 made of resin and glass fibre.

In a limiting case, this stress load can lead to the collapsing or busting of the hose in two ways; either by bowing-out in a plane tangential to the helix or by a spatial bend.

Experiments have proved that a spatial bend occurs at smaller stress loads and the load bearing capability of the hose is improved if the ratio bla (Figure 6) is chosen such that the probability of the formation of a planar bow and a special bow should be at least equal. In this case, b = 1.4a.

By keeping the tensile rigidity of the hose at a desirable level and the advantageous vibration damping properties of the hose enable this ratio of b to a to be increased without the risk of the collapsing of the hose. Hence in all cases b should be at least 1.4 times a.

The modulus of elasticity expressing the tensile rigidity of the hose would depend only on the modulus of elasticity of the reinforcing cords 7 and 8 and on the modulus of elasticity of the core 3, consisting of resin and glass fibre, if the two inserts are placed directly on top of each other. The interposed cushion layer 6 gives the possibility of controlling or selecting the desirable elasticity. The tensile rigidity can be further reduced, in addition to the effect of the cushion layer 6 by increasing the ratio tib.

Among the hydraulic characteristics of the hose, the dynamic vibration damping is a very important one. The cushion layer 6 which is interposed between the stiffening and reinforcing layers of the hose and the spacer layer 4 arranged in the gap t, can absorb and store substantial deformation forces. In other words, the hose may with advantage be used in hydraulic systems working with very unevenly acting large pressure-shocks.

The change in the length of the hose caused by the effect of an internal pressure, depends not only on the design of the angles of reinforcing cords 7 and 8, but on the dimension of the core 3 and the spacer layer 4. Any increase in the width b and a reduction in the size of the gap t results in the core 3 (consisting of resin and glass fibre) taking up a proportion of the internal pressure, thus imparting a stretching effect to the other layers. Conversely, a change of these dimensions in the opposite sense, can result in a layer-shortening tendency, in view of the steep angles of the reinforcing cords 7 and 8 of the hose.

The dynamic effects of the hose, as described above, can be applied in any convenient combination. By selecting the dimensions a, b and t for the structure of core 3, consisting of resin and glass fibre, a hose with the best characteristics to suit to any given mechanical system can be constructed.

The constructions according to the preferred embodiments of the invention have in addition to the advantages described above, a further substantial advantage i.e. the field of application is much greater than that of known hoses.

In the embodiments of Figures 1 and 6 to 8, the core 3 is bonded to the surrounding rubber jacket or coating 2 simultaneously with bonding of the latter to the rubber layer 1. In the appended claim 1, the first to sixth layers are provided by components 2 and 3, 5, 6, 7 and 8, 9 and 10 of. the embodiments shown in the drawings.

WHAT WE CLAIM IS: 1. A cylindrical hose suitable for withstanding any one of a combination of internal and/or external pressures or vacuum, a tensile load and a torsional load, comprising a plurality of adjoining layers which taken in a radially outward direction include: a first layer comprising a helical core of fibre and resin material wholly or partially embedded in a rubber jacket, the helical core having an elongated cross-sectional shape with a length, in a direction parallel to the central longitudinal axis of the hose, greater than a width, in the direction perpendicular to said central longitudinal axis, in the ratio of at least 1.4 to 1, the helical core and the rubber jacket being simultaneously formed into a space lattice, a second layer which comprises a ply of fabric material for stress distribution, a third layer of rubber which serves as a cushion layer to provide flexibility, a fourth layer which comprises reinforcing stiffeners encircling the longitudinal axis of the hose, a fifth layer which comprises a ply of fabric material and a sixth layer which comprises an outer protective rubber covering.

2. A hose according to claim 1, wherein the fibre and resin material is wholly embedded in the rubber jacket and the first layer is covered on its radially inner surface by an internal rubber layer the radially inner surface of which defines the flow-confining wall of the hose, the fibre and resin material being bonded to the rubber jacket to form said first layer simultaneously with bonding of the rubber jacket to the internal rubber layer.

3. A hose according to claim 1 or 2, wherein the fibre is glass fibre.

4. A hose according to claim 1, 2 or 3 wherein the fibre is stranded glass fibre.

5. A hose according to claim 1 wherein the fibre is of steel, carbon, boron, an aramide, an imide or an amide fibre.

6. A hose according to any preceding claim, wherein the helix of fibre and resin material contains one or more embedded

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. wound core 3 made of resin and glass fibre. In a limiting case, this stress load can lead to the collapsing or busting of the hose in two ways; either by bowing-out in a plane tangential to the helix or by a spatial bend. Experiments have proved that a spatial bend occurs at smaller stress loads and the load bearing capability of the hose is improved if the ratio bla (Figure 6) is chosen such that the probability of the formation of a planar bow and a special bow should be at least equal. In this case, b = 1.4a. By keeping the tensile rigidity of the hose at a desirable level and the advantageous vibration damping properties of the hose enable this ratio of b to a to be increased without the risk of the collapsing of the hose. Hence in all cases b should be at least 1.4 times a. The modulus of elasticity expressing the tensile rigidity of the hose would depend only on the modulus of elasticity of the reinforcing cords 7 and 8 and on the modulus of elasticity of the core 3, consisting of resin and glass fibre, if the two inserts are placed directly on top of each other. The interposed cushion layer 6 gives the possibility of controlling or selecting the desirable elasticity. The tensile rigidity can be further reduced, in addition to the effect of the cushion layer 6 by increasing the ratio tib. Among the hydraulic characteristics of the hose, the dynamic vibration damping is a very important one. The cushion layer 6 which is interposed between the stiffening and reinforcing layers of the hose and the spacer layer 4 arranged in the gap t, can absorb and store substantial deformation forces. In other words, the hose may with advantage be used in hydraulic systems working with very unevenly acting large pressure-shocks. The change in the length of the hose caused by the effect of an internal pressure, depends not only on the design of the angles of reinforcing cords 7 and 8, but on the dimension of the core 3 and the spacer layer 4. Any increase in the width b and a reduction in the size of the gap t results in the core 3 (consisting of resin and glass fibre) taking up a proportion of the internal pressure, thus imparting a stretching effect to the other layers. Conversely, a change of these dimensions in the opposite sense, can result in a layer-shortening tendency, in view of the steep angles of the reinforcing cords 7 and 8 of the hose. The dynamic effects of the hose, as described above, can be applied in any convenient combination. By selecting the dimensions a, b and t for the structure of core 3, consisting of resin and glass fibre, a hose with the best characteristics to suit to any given mechanical system can be constructed. The constructions according to the preferred embodiments of the invention have in addition to the advantages described above, a further substantial advantage i.e. the field of application is much greater than that of known hoses. In the embodiments of Figures 1 and 6 to 8, the core 3 is bonded to the surrounding rubber jacket or coating 2 simultaneously with bonding of the latter to the rubber layer 1. In the appended claim 1, the first to sixth layers are provided by components 2 and 3, 5, 6, 7 and 8, 9 and 10 of. the embodiments shown in the drawings. WHAT WE CLAIM IS:

1. A cylindrical hose suitable for withstanding any one of a combination of internal and/or external pressures or vacuum, a tensile load and a torsional load, comprising a plurality of adjoining layers which taken in a radially outward direction include: a first layer comprising a helical core of fibre and resin material wholly or partially embedded in a rubber jacket, the helical core having an elongated cross-sectional shape with a length, in a direction parallel to the central longitudinal axis of the hose, greater than a width, in the direction perpendicular to said central longitudinal axis, in the ratio of at least 1.4 to 1, the helical core and the rubber jacket being simultaneously formed into a space lattice, a second layer which comprises a ply of fabric material for stress distribution, a third layer of rubber which serves as a cushion layer to provide flexibility, a fourth layer which comprises reinforcing stiffeners encircling the longitudinal axis of the hose, a fifth layer which comprises a ply of fabric material and a sixth layer which comprises an outer protective rubber covering.

2. A hose according to claim 1, wherein the fibre and resin material is wholly embedded in the rubber jacket and the first layer is covered on its radially inner surface by an internal rubber layer the radially inner surface of which defines the flow-confining wall of the hose, the fibre and resin material being bonded to the rubber jacket to form said first layer simultaneously with bonding of the rubber jacket to the internal rubber layer.

3. A hose according to claim 1 or 2, wherein the fibre is glass fibre.

4. A hose according to claim 1, 2 or 3 wherein the fibre is stranded glass fibre.

5. A hose according to claim 1 wherein the fibre is of steel, carbon, boron, an aramide, an imide or an amide fibre.

6. A hose according to any preceding claim, wherein the helix of fibre and resin material contains one or more embedded

electrical conductor(s).

7. A hose according to any preceding claim, wherein the resin is a synthetic epoxy resin.

8. A hose according to any one of claims 1 to 6, wherein the resin is a synthetic phenolic resin.

9. A hose according to any one of the preceding claims, wherein there are a plurality of helical cores in said first layer, the helical cores being angularly displaced around the longitudinal axis of the hose so as to be interlaced.

10. A hose according to claim 9, wherein adjacent turns of the helical cores and their rubber jackets are separated by a spacer layer.

11. A hose substantially as herein described with reference to Figure 1 or Figure 2 or Figures 3 and 4 or Figure 5 or Figures 6 and 7 or Figure 8 of the accompanying drawings.