IT201800005827A1 - REINFORCED FLEXIBLE HOSE, AS WELL AS THE APPARATUS AND METHOD FOR MAKING THE SAME - Google Patents

Description

REINFORCED FLEXIBLE HOSE, AS WELL AS THE APPARATUS AND METHOD FOR MAKING THE SAME

DESCRIPTION

Field of application

The present invention is generally applicable to the technical field of flexible pipes, and particularly relates to an apparatus and a method for manufacturing a flexible pipe reinforced with at least one textile layer.

The invention also relates to a reinforced flexible hose that can be made using the above method and apparatus.

Definitions

In this text, the term "textile thread" or derivatives refers to an elongated filiform element of any shape and in any material, provided that the dimension of the length is significantly prevailing over the others. For example, the textile thread may be a polymeric thread, which may have a unitary structure or may in turn consist of the union of several elementary threads, or a textile band with any section.

In this text, the term "textile layer knitted with a tricot type chain link" and the like means a layer consisting of at least two threads or groups of threads laid on a load-bearing layer and intertwined ("knitted") to form a plurality of “tricot” type chain links. Preferably, the "textile layer knitted with a tricot-type chain link" can be arranged on the layer which supports it so as to leave free portions thereof.

In the present text, the term "knit in a tricot type chain" and the like means the portion of textile thread (or set of threads grouped into a single thread) which is intertwined with the adjacent threads to form a loop having a generally annular.

In this text, the term "row of links" and the like of a textile layer knitted with tricot-type chain links means the line defined by the "tricot-type chain links" linked to each other.

In this text, the term "rows of meshes" and the like of a textile layer knitted with tricot-type chain links means the set of portions of textile thread (or set of threads grouped into a single thread) that connect between their two consecutive “tricot-type chain links” along the same thread.

In this text, the term "predisposition" or derivatives means the preparation of an element of interest for a phase of the process of interest, thus including any preventive treatment aimed at optimally carrying out the same phase of interest, from the simple withdrawal and possible storage for thermal and / or chemical and / or physical and similar pre-treatments.

In this text, unless otherwise specified with the term "inclination" or derivatives of a textile layer or part of it, we mean the inclination of the textile layer or part of it with respect to the axis of the tube.

State of the art

Flexible pipes are known which comprise an internal layer capable of coming into contact with the liquid to be transported, an external layer capable of being grasped by a user and, interposed between these, a textile layer knitted with chain links of the tricot type.

From the European patent EP-B1-0623776, in the name of the same Applicant, an example of this tube is known, in which the rows of meshes and the rows of meshes of the textile layer have opposite inclinations with respect to the axis of the tube.

This type of flexible hose has good anti-torsion properties, good malleability and relatively high bursting pressure, and is also easy to produce in line.

This known type of flexible pipes, however, has excessive expansion under pressure, which is potentially dangerous especially at the junction with a fitting. At this point, in fact, excessive expansion can lead to liquid leaks and / or breakages.

Furthermore, the internal pressure of the tube puts tension on the textile threads of the knitted layer, in particular in correspondence with the intertwining points between the stitches, which over time become potential weak points of the tube.

Furthermore, these known flexible tubes can be improved in terms of aesthetic appeal and duration.

Presentation of the invention

The object of the invention is to at least partially overcome the drawbacks encountered above, by providing an apparatus and / or a method for making a reinforced flexible pipe and / or a reinforced flexible pipe of marked efficiency and relative cheapness.

Another object of the invention is to provide an apparatus and / or a method which allow the production of a reinforced flexible tube in a relatively simple and fast way.

Another object of the invention is to provide an apparatus and / or a method which allow the production of a long-lasting reinforced flexible hose.

Another object of the invention is to make available an apparatus and / or a method which allow the production of a reinforced flexible tube with high aesthetic appeal.

These objects, as well as others which will appear more clearly in the following, are achieved by the apparatus, the method and the reinforced flexible tube in accordance with what is described, illustrated and / or claimed herein.

Advantageous embodiments of the invention are defined in accordance with the dependent claims.

Brief description of the drawings

Further characteristics and advantages of the invention will become more evident in the light of the detailed description of some preferred but not exclusive embodiments of the invention, illustrated by way of non-limiting example with the aid of the accompanying drawing tables in which:

FIG. 1 is a schematic view of an embodiment example of an apparatus 10 for manufacturing the reinforced flexible tube 1;

FIG. 2 is a schematic view of an embodiment example of a knitting station 12, with in FIG. 2A a front view of the knitting unit 22 forming part of this station;

FIG. 3 is a schematic view of an embodiment example of a flexible tube 1 with a reinforcing layer 4;

FIG. 4 is an enlarged view of the reinforcement layer of the reinforced hose 1 of FIG.1.

Detailed description of a preferred embodiment example With reference to the aforementioned figures, the flexible tube according to the invention, globally indicated with the number 1, can be composed of an internal supporting tubular layer 2, which can be made for example of plasticized PVC or in elastomer or thermoplastic elastomer (TPE), from an external tubular covering layer 3, which can, for example, always be made of plasticized PVC or elastomer or thermoplastic elastomer (TPE) and, interposed between these, by at least one textile layer 4 which can be made for example of polyester yarn.

The internal tubular bearing layer 2, which can define the X axis of the tube 1, may be intended to come into contact with the liquid to be transported, while the outer covering layer 3 may be intended to be grasped by a user.

In a preferred but not exclusive embodiment of the invention, the tube 1 may comprise a textile layer 4 which may be of the knitted type with chain links of the tricot type, indicated with 6, 6 ', 6' '... The textile layer 4 can therefore have rows of stitches 7, 7 'and rows of stitches 8, 8' in any number.

Even if for the sake of simplicity a single textile layer made from a single knitting unit is described in the present text, it is clear that the tube may include several textile layers made from one or more knitting units. More generally, other additional layers, both textile and polymeric, may also be provided between the aforementioned layers of the tube 1, without departing from the limits of protection expressed by the content of the attached claims.

In the textile reinforcement layer 4 the rows of links 8, 8 'can be equidistant from each other, as well as the rows of links 7, 7'.

In other words, the distance R between two consecutive rows of stitches 8, 8 'will be the same for all the rows of stitches of the textile reinforcement layer 4. Likewise, the distance F between two consecutive rows of stitches 7, 7' will be the same for all the rows of meshes of the textile reinforcement layer 4.

Advantageously, the rows of links 7, 7 'can be grouped in a first group of a row of narrow-configuration links 7 and a second group of a row of meshes 7' with a wide configuration mutually alternating with each other.

Although in the embodiment illustrated here the rows of links are grouped into four groups with a narrow configuration and four groups with a wide configuration and each group is composed of a single row of links, it is understood that the groups can be in any number and each group may be composed of any number of rows of meshes without thereby departing from the scope of protection of the attached claims.

Conveniently, the row of stitches 7 of the first group can be placed side by side with the row of stitches 7 'of the second group.

It is understood that in the case of groups with several rows of links, at least one row of the first group can be flanked by at least one row of the second group, without thereby departing from the attached claims.

More specifically, the row of narrowly configured links 7 may have a distance D1 between the mutual interlacing points 16 ', 16' 'of two consecutive links 6, 6', 6 '' which is significantly lower than the distance D2 between the points of reciprocal interlacing 160 ', 160' 'of two consecutive stitches 6, 6', 6 '' of the row of stitches 7 'with a wide configuration.

Conveniently, the ratio between the above distances D1 and D2 can be at least 1: 4, preferably at least 1: 5 and even more preferably at least 1: 6.

In this way a tube will be obtained having a good bursting pressure, absolutely comparable to conventional knitted tubes of the state of the art for the same number of textile threads, and which retains a good malleability.

On the other hand, with the same number of textile threads, it has a much lower number of meshes, which means fewer points of potential breakage and therefore greater durability and reliability over time.

This characteristic also means greater control of the expansion of the pipe under pressure, which avoids the problems of potential leaks and breakages in correspondence with the fittings of the knitted pipes of the state of the art.

In practice, the flexible tube 1 described above retains all the advantages of a knitted tube and also has a low radial expansion, typical of anilox tubes.

Furthermore, the overall visual effect of the knitted layer 4 is particularly pleasant, which gives the flexible tube 1 a high aesthetic appeal. For this purpose, the outer layer 3 can preferably be made of optically transparent material or configured in such a way as to allow the underlying textile layer 4 to be seen and / or perceived to the touch.

In a preferred but not exclusive embodiment, the rows of links 7, 7 'and the rows of links 8, 8' may have substantially opposite inclinations α, β with respect to the X axis of the tube, so that the textile layer 4 has an overall spiral course along the tube 1.

On the other hand, the textile layer 4 can be configured as a classic knitted tricot, with rows of meshes 7, 7 'substantially parallel to the axis of the tube and rows of meshes 8, 8' substantially inclined with respect to the same X axis.

On the other hand, the textile layer 4 can be configured according to the teachings of the international application PCT / IB2017 / 058257, in the name of the same Applicant, with rows of meshes 7, 7 'substantially inclined with respect to the axis of the tube and rows of meshes. 8, 8 'substantially parallel to the same X axis.

Conveniently, the flexible hose 1 can be particularly, though not exclusively, usable as an irrigation hose for domestic use, for example as a so-called garden hose.

On the other hand, depending on the configuration of the textile layer, and in particular even if not exclusively on the pitch and / or the quantity per linear meter and / or the count of the textile threads, the flexible tube 1 can reach relatively high bursting pressures. , and therefore be usable for various purposes.

Advantageously, the first and second materials of the inner 2 and outer tubular layers 3 may be of the thermoplastic or elastomeric or thermoplastic polymeric type.

Conveniently, the first and second materials can both be polymeric with a plasticized PVC (polyvinyl chloride) based matrix. Both the first and the second polymeric material may have Shore A hardness between 40 and 100, preferably 60 and 90.

On the other hand, the first and second materials may be thermoplastic elastomers, for example TPE-U, TPE-O, TPE-V, TPE-S, TPE-E, or elastomers, such as for example natural rubber, butyl, EPDM , Chloroprene, SBR, silicone.

It is understood that even if in the following we will refer to plasticized PVC for simplicity, the first and second material of the internal 2 and external 3 tubular layers may be whatever, always going out of the scope of protection of the attached claims.

The flexible tube 1 can be produced by means of the apparatus 10 illustrated in FIG.1. Initially, by introducing plasticized PVC into a first extruder 11, the internal tubular layer 2, intended to act as a load-bearing layer, will be extruded in a per se known manner.

Then, the load-bearing layer will be introduced into a knitting station 12, suitable for making the textile layer 4 on the internal tubular load-bearing layer 2.

Finally, the reinforced tubular semi-finished product 13 thus obtained will be introduced into a second extruder 14, loading it from above with plasticized PVC, so as to extrude, in a per se known manner, the covering layer 3 on the upper surface of the reinforced tubular semi-finished product 13, obtaining at the outlet 24 from the second extruder 14 the finished tube 1.

For the purposes of manufacturing the textile layer 4, the knitting station 12 may comprise an inlet 21 for the internal supporting tubular layer 2 coming from the first extruder 11, a circular knitting unit 22 and an outlet 24 'for the reinforced tubular semi-finished product 13 , intended for the second extruder 14.

The arrow W in FIG. 2 indicates the direction of advancement of the supporting layer 2 through the circular meshing station 12, and also defines a longitudinal axis which coincides with the X axis of the tube. Externally to the knitting station 12, known means for pulling the tube along the feed line X may be provided.

The circular knitting unit 22 may have a series of needles 26, 27, fixed in a needle-holder cage 28, which are operatively connected to a distributor 38 and, by means of tensioning and return means, known per se, to a series of spools 32 of textile thread 34, mounted on spool holders 36.

In use, the needles 26, 27 in a per se known manner will be able to take the respective textile thread 34 from the corresponding bobbin 32 to weave it with the adjacent threads and form knits 6 of the tricot type.

The needles 26, 27 can be mounted on the needle holder cage 28 peripherally around the X axis, so as to form the textile layer 4 on the outer surface of the inner tubular layer 2 carrying in advance.

As particularly illustrated in FIG. 2, the needles 26, 27 may have respective ends 26 ', 27' operatively coupled with cam means, generally indicated with 50, to promote their reciprocating movement along respective directions substantially parallel to the longitudinal axis X.

In a per se known manner, the rotation of the cam means 50 will promote the reciprocating linear movement along axes parallel to the X axis.

In addition, any rotation of the needle holder cage 28 will rotate the needles 26, 27 around the X axis.

Conveniently, the number of knitting needles 26, 27 may be any, as well as the number of coils 32. For example, for the tube illustrated in FIGS. 3 and 4 8 reels of textile thread and 8 knitting needles can be used.

In a per se known manner, the distributor 38 may have a minimum number of seats 38 'equal to the number of coils 32 and / or the number of crests of the cam means 50. Conveniently, the number of coils 32 and that of the crests of the means cam 50 may be the same, for example, for the tube illustrated in FIGS. 3 and 4 each of the seats 38 'of the distributor 38 can be operationally connected with a respective reel 32 in order to accommodate the relative textile thread 34, with a number of reels 32 equal to the number of seats 38' of the distributor 38.

As mentioned above, for the tube illustrated in FIGS. 3 and 4 8 reels of textile thread and a distributor 38 having 8 seats 38 'may be used, each thread being connected with a respective seat.

In order to obtain the effect illustrated in FIGS. 3 and 4, the needles 26, 27 can be grouped into a predetermined number of groups, for example four groups, equally distributed on the needle holder 28.

As particularly illustrated in FIG. 2A, each group may include two or more needles 26, 27 equidistant from each other by a first mutual angular distance d1.

Advantageously, moreover, two consecutive groups may have a second predetermined mutual angular distance d2 greater than the distance d1.

More in detail, the ratio between the angular distance d1 and the angular distance d2 may be greater than 1.5, preferably between 1.5 and 3 and more preferably between 1.5 and 2.5.

For example, for the tube illustrated in FIGS. 3 and 4, the needles can be grouped into four groups of two needles, spaced apart by about 30 °. The angular distance d2 between two groups of needles can be about 60 °.

In other words, each group may preferably contain the same number of needles spaced apart by the angular distance d2, and each group may have a distance from the previous and subsequent group equal to the angular distance d1.

The reciprocal inclination of the rows of stitches 7, 7 'and rows of stitches 8, 8' can be adjusted by the relative rotary motion of the needles 26, 27 and that of the coils 32 and of the distributor 38.

For example, for the tube illustrated in FIGS. 3 and 4, the needles 26, 27 can rotate by means of special actuator means acting on the needle-holder cage 28 around the axis X in a predetermined direction V1, while the distributor 38 and the coils 32 can rotate by means of special actuator means around the axis X in a predetermined direction V2 opposite to the direction V1.

On the other hand, to make a classic tricot knitted tube, the needles 26, 27 can remain rotationally stationary while the distributor 38 and the coils 32 can rotate.

Furthermore, to realize a textile layer 4 configured according to the teachings of the international application PCT / IB2017 / 058257, in the name of the same Applicant, with rows of meshes 7, 7 'substantially inclined with respect to the axis of the tube and rows of meshes 8, 8 'substantially parallel to the same X axis, the needles 26, 27 can rotate while the distributor 38 and the reels 32 can remain rotationally stationary.

In order to promote the rotation of the above components, actuator means known per se may be provided, for example a motor with relative belt.

From what has been described above, it is clear that the invention achieves the intended purposes.

The apparatus and the method of manufacturing the flexible tube 1 are susceptible of numerous modifications and variations, all of which fall within the inventive concept expressed in the attached claims. All the details can be replaced by other technically equivalent elements, and the materials can be different according to the requirements, without departing from the scope of protection of the attached claims.

It is also understood that in a further aspect a flexible tube reinforced with at least one internal polymeric or elastomeric bearing layer, at least one external polymeric or elastomeric layer and a single textile layer interposed between these interposed knitted with chain links of the tricot type in which the rows of links are substantially parallel to each other and to the axis of the tube and the rows of links are inclined with respect to the axis of the tube.

Claims (10)

CLAIMS 1. An apparatus for making a flexible hose reinforced with at least one textile layer, comprising: - an inlet (21) for at least one internal supporting tubular layer (2) defining a longitudinal axis (X) made of at least a first polymeric or elastomeric or thermoplastic elastomeric material; - at least one circular knitting unit (22) to form on said at least one internal tubular bearing layer (2) at least one textile layer (4) knitted with chain links (6) of the tricot type having rows of links (8, 8 ') and rows of links (7, 7'), so as to form a reinforced tubular semi-finished product (13); - means (14) for making at the top of said reinforced tubular semi-finished product (13) at least one outer covering layer (3) in at least one second polymeric or elastomeric or thermoplastic elastomeric material to obtain the reinforced flexible tube (1); - an outlet (24) for the reinforced flexible hose (1); wherein said at least one circular mesh unit (22) comprises: - a series of reels (32) of textile threads (34); - at least one yarn distributor (38) operatively connected with said coils (32); - a needle-holder cage (28) with a series of knitting needles (26, 27); - cam means (50) operatively connected with said needles (26, 27) to promote their reciprocating movement along respective directions substantially parallel to said longitudinal axis (X); wherein said needles (26, 27) are grouped in a predetermined number of groups equally distributed on said needle holder (28), each group including at least two needles (26, 27) equidistant from each other by a first predetermined mutual angular distance (d1), two consecutive groups having a second predetermined mutual angular distance (d2) greater than said first predetermined mutual angular distance (d1); so that said at least one knitted textile layer (4): - there are rows of meshes (8, 8 ') and rows of meshes (7, 7') equidistant from each other; - there are rows of links (7, 7 ') grouped in at least a first group of one or more rows of narrow-configuration links (7) and at least a second group of one or more rows of links (7') with a wide configuration between reciprocally alternating with each other, at least one row of links (7) of said at least one first group being flanked by at least one row of links (7 ') of said at least one second group. 2. Apparatus according to claim 1, wherein the ratio between said second predetermined angular distance (d2) and said first predetermined angular distance (d1) is greater than 1.5, preferably between 1.5 and 3 and more preferably between 1.5 and 2.5. 3. Apparatus according to claim 1 or 2, in which each of said needles (26, 27) has a rear end (26 ', 27') operatively coupled with said cam means (50). 4. Apparatus according to claim 1, 2 or 3, further comprising first actuator means acting on said needles (26, 27) to promote their rotation around said axis (X) in a first predetermined direction (V1) and second actuator means acting on said distributor (38) and said reels (32) to promote their rotation around said axis (X) in a second predetermined direction (V2) opposite to said first predetermined direction (V1), so that said knitted textile layer (4 ) with tricot-type chain links (6, 6 ') present said rows of links (8, 8') and said rows of links (7, 7 ') having predetermined inclination (α, β) substantially opposite to said axis (X). 5. A method for making a reinforced flexible hose, comprising in sequence the steps of: a) provision of at least one internal supporting tubular layer (2) defining a longitudinal axis (X) made of at least a first thermoplastic polymeric or elastomeric or elastomeric material; b) realization on said at least one internal tubular bearing layer (2) of at least one textile layer (4) knitted with chain links (6) of the tricot type having rows of links (8, 8 ') and rows of links (7, 7 '), so as to obtain a reinforced tubular semi-finished product c) realization above said reinforced tubular semi-finished product (13) of at least one outer covering layer (3) made of at least a second polymeric or elastomeric or thermoplastic elastomeric material to obtain the tube reinforced hose (1); wherein said at least one circular mesh unit (22) comprises: - a series of reels (32, 33) of textile threads (34, 35); - at least one yarn distributor (38) operatively connected with said coils (32); - a needle-holder cage (28) with a series of knitting needles (26, 27); - cam means (50) operatively connected with said needles (26, 27) to promote their reciprocating movement along respective directions substantially parallel to said longitudinal axis (X); in which said needles (26, 27) are grouped in a predetermined number of groups equally distributed on said needle holder (28), each group including at least two needles (26, 27) equidistant from each other by a first predetermined mutual angular distance (d1), two consecutive groups having a second predetermined mutual angular distance (d2) greater than said first predetermined mutual angular distance (d1); so that said at least one textile layer (4): - there are rows of meshes (8) and rows of meshes (7, 7 ') equidistant from each other; - there are rows of links (7, 7 ') grouped in at least a first group of one or more rows of narrow-configuration links (7) and at least a second group of one or more rows of links (7') with a wide configuration between reciprocally alternating with each other, at least one row of links (7) of said at least one first group being flanked by at least one row of links (7 ') of said at least one second group. 6. A reinforced flexible tube comprising at least one internal supporting tubular layer (2) defining a longitudinal axis (X) made of at least a first polymeric or elastomeric or thermoplastic elastomeric material, at least one external covering layer (3) made in at least a second polymeric or elastomeric or thermoplastic elastomeric material and at least one reinforcing textile layer (4) interposed between said inner (2) and outer (3) layer, in which said at least one reinforcing textile layer (4) is a knitted layer with mesh in chain (6, 6 ', 6' ') of tricot type with rows of links (8, 8') and rows of links (7, 7 ') equally spaced apart, said rows of links (7, 7') being grouped in at least a first group of one or more rows of narrow-configuration links (7) and at least a second group of one or more rows of wide-configuration links (7 ') mutually alternating with each other, at least one row of links (7) of said at least one first group being flanked at least one row of links (7 ') of said at least one second group. 7. Flexible hose according to the preceding claim, in which each of said links (6) is linked with the previous or subsequent link (6 ', 6' ') in at least two points (16', 16 ''; 160 ', 160 '') of mutual interlacing, the first distance (D1) between the points of reciprocal interlacing (16 ', 16' ') of the stitches (6, 6', 6 '') of the rows of stitches (7) of said first group being considerably less than the second distance (D2) between the points of mutual interlacing (160 ', 160' ') of the links (6, 6', 6 '') of the rows of links (7 ') of said second group. Flexible hose according to the preceding claim, wherein the ratio between said first distance (D1) and said second distance (D2) is at least 1: 4, preferably at least 1: 5 and even more preferably at least 1: 6. 9. Flexible hose according to claim 6, 7 or 8, wherein two consecutive rows of links (8, 8 ') have a substantially constant third mutual distance (R) for all rows of links (8, 8') of said at least one textile reinforcement layer (4), two consecutive rows of stitches (7, 7 ') have a fourth mutual distance (F) substantially constant for all the rows of stitches (7, 7') of said at least one textile layer of reinforcement (4). Flexible hose according to any one of claims 6 to 9, wherein said knitted textile layer (4) with chain links (6, 6 ') of the tricot type has said rows of links (8, 8') and said rows of links (7, 7 ') having predetermined inclination (α, β) substantially opposite with respect to said axis (X).