GB2369170A

GB2369170A - Hose with elastomeric and textile layers

Info

Publication number: GB2369170A
Application number: GB0123555A
Authority: GB
Inventors: Horacio Ferrer; Alladino Borghese; Raul Zanetti
Original assignee: Uniflex Utiltime SpA
Current assignee: Uniflex Utiltime SpA
Priority date: 2000-10-16
Filing date: 2001-10-01
Publication date: 2002-05-22
Anticipated expiration: 2021-10-01
Also published as: ITPN20000035U1; DE20114122U1; GR2002378Y; IT251754Y1; ES1050176Y; FR2815392B3; GB0123555D0; GB2369170B; FR2815392A1; ES1050176U

Abstract

Hose for irrigation comprising an inner tubular layer and an outer tubular layer both made of elastomeric material, preferably PVC, and two intermediate reinforcing textile layers. The innermost textile layer (13) is made of a warp-knitted fabric and the outermost textile layer (14) is produced with yarns interlaced to form a net. This type of hose offers a good compromise that satisfies the contrasting demands, required by the different uses, of elasticity and stiffness.

Description

HOSE FOR IRRIGATION

The present innovation relates to a hose produced with an elastomer reinforced by textile layers for distributing fluids under pressure, particularly for use in 5 irrigation systems.

For irrigation purposes, use is often made of a variety of kinds of hose such as, for example, rigid polyvinyl chloride hose of variable diameter and thickness depending on the operating pressure; polyethylene hose; polypropylene hose; polyester resin pipes; PVC or polypropylene pipes coated with polyester resin; and hose made from 10 an elastomer and reinforced with superimposed textile layers of various kinds.

The best quality and most widely used types of hose are those with textile reinforcements. This type of hose must fulfil multiple demands: they must have high resistance to the internal pressure of the fluid, have walls that are not too thick, be sufficiently flexible to allow them to be wound on reels and, above all, must resist the 15 twisting effect produced by the spiral pattern of the weft of the fabric.

Various of these technical problems have been addressed and solved by different means.

German Patent DE 197 27 142, for example, shows a hose for irrigation consisting of an internal tubular layer of plasticized PVC, around which is wrapped a 20 reinforcing layer of interlaced polyester yarn coated with a microlayer of plasticized PVC, over which is laid a knitted reinforcing fabric made of polyester yarn which is finally covered with a cylindrical outer layer, again of PVC. This solution gives a hose which, although having a better antitwist behaviour than previously known hose, has the disadvantage of unacceptable stiffness due to the thickness of the walls of the hose and 25 hence to the diameter because of the multiplicity of layers of fabric and PVC employed.

Italian patent application PN2000A000030 by the present Applicant discloses the insertion of two layers of knitted (so-called "tricot") fabric in the body of the hose, with the loops of one layer at an opposite angle to the loops of the second layer. This solution further improves the antitwist behaviour of the hose, but reduces its stiffness to 30 such an extent as to make the hose unsuitable for some applications. Specifically, under the action of the internal pressure of the fluid, the textile loops tend to give and the hose tends to expand.

-2 It is an object of the present innovation to find a good compromise so as to provide a type of hose capable of satisfying the diverse and opposing requirements imposed by differing uses.

According to the present invention, there is provided t1] 5 The invention will be further described by way of non-limitative example with reference to the accompanying drawings, in which: Figure 1 is a sectional perspective view of a length of hose produced in accordance with the innovation; Figure 2 shows the hose of Figure 1 in cross section.

10 With reference to the figures, these show schematically, in perspective and in section, a length of hose consisting of an inner tubular layer 11 and an outer tubular layer 12, both made of elastomeric material, preferably PVC.

According to the present invention, a first reinforcing textile layer 13 made of warp-knitted (so-called "tricot") fabric is wrapped in a spiral around the inner tubular 15 layer 11. This textile reinforcement has its warp lines at an angle to the axis of the hose and its weft lines roughly parallel to the axis of the hose, thus giving the wall of the hose certain elasticity.

A second reinforcing textile layer 14 is wound in a spiral around the first reinforcing textile layer 13. The second reinforcing textile layer 14 is formed from yarns 20 interlaced to form a net. The reinforcing layer 14 makes it possible to oppose the tendency of the hose to twist when the fluid passes through it under pressure. The two reinforcing textile layers 13 and 14 are preferably separated by a thin layer of material 15 which is also of elastomer and preferably in PVC.

This solution has been demonstrated experimentally to be the best at 25 satisfying the diverse use requirements for this type of hose. Specifically, by laying the knitted reinforcing layer 13 in a more inward position than the interlaced reinforcing layer 14, the result is a hose which in operation is effective at absorbing the internal pressure of the fluid because of the elasticity of the knitted layer 13, which can expand. However, the expansion of the layer 13 is contained and controlled by the presence of the outermost 30 textile layer 14 which, being interlaced, cannot expand.

The illustrated hose is therefore appropriately flexible, but at the same time highly resistant to potential hydraulic ram effects and to the tensile stresses applied to the hose when in operation. For equal performance, a hose of this kind also has less density

-3 than similar hose having textile reinforcements of a different type or laid differently in the body of the hose. This is because the specific positioning of the textile reinforcements makes it possible to avoid the need for an intermediate layer, however thin, of elastomer, or to reduce the thickness of the inner and outer layers of elastomer.

Claims

1. A hose comprising an inner tubular layer and an outer tubular layer of elastomeric material interposed between which two layers are two layers of reinforcing 5 textile material, wherein the innermost textile layer is made of a warp-knitted or tricot fabric.

2. A hose according to Claim 1, wherein the outermost textile layer is

produced with yarns interlaced to form a net.

3. A hose according to Claim 1 or 2, wherein the material of the tubular layers is PVC.

4. A hose according to Claim l or 3, wherein another concentric layer of thin 15 hose, made of elastomeric material is interposed between the said two layers of reinforcing textile material.

5. A hose according to Claim 4, wherein said another layer is made of PVC.

20

6. A hose constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.