Multilayer tube, particularly for chemical and food-related fluids

Abstract

A multilayer tube, particularly for chemical and food-related fluids, which includes, in succession from the inside outward a first layer constituted by a tubular sheath that is at least externally corrugated and which defines the duct for the fluid. The tube further includes at least one second layer, which has an inner layer, chosen from between a rubberized fabric and an elastomeric material with textile reinforcement, which is arranged on the first layer, and an outer covering which is arranged on the inner layer.

Claims

1. A multilayer tube, for chemical and food-related fluids, which comprises, in succession from the inside outward: a first layer constituted by a tubular sheath that is at least externally corrugated and which defines a duct for fluid, and at least one second layer, which comprises an inner layer, chosen from between a rubberized fabric and an elastomeric material with textile reinforcement, arranged on said first layer, and an outer covering arranged on said inner layer, wherein said first layer is constituted by a tubular sheath which is externally corrugated in a screw manner so as to define a plurality of peaks and troughs, and said second layer is shaped internally as a female thread, such that the second layer is screwable into and is unscrewable from the first layer.

2. The multilayer tube according to claim 1, wherein said tubular sheath, which constitutes said first layer, is smooth on an inner side configured for passage of fluid.

3. The multilayer tube according to claim 1, wherein said first layer is constituted by a fluorinated polymer chosen from among Fluorinated Ethylene Propylene (FEP), Tetrafluoroethylene Perfluoromethylvinylether (MFA), Perfluoroalkoxy alkanes (PFA), Polyvinylidene Difluoride (PVDF), Ethylene Chlorotrifluoroethylene (ECTFE), and Polytetrafluoroethylene (PTFE).

4. The multilayer tube according to claim 1, wherein said first layer is transparent.

5. The multilayer tube according to claim 1, wherein said first layer is white.

6. The multilayer tube according to claim 1, wherein said first layer is colored.

7. The multilayer tube according to claim 1, wherein said first layer is conductive.

8. The multilayer tube according to claim 1, wherein the rubberized fabric of said inner layer is constituted by a material chosen among aramid, glass fiber, poly-para-phenylene terephthalamide, polyester, rayon and nylon.

9. The multilayer tube according to claim 1, wherein the rubberized fabric of said inner layer has a tubular structure that wraps around said first layer.

10. The multilayer tube according to claim 1, wherein said outer covering comprises at least one layer made of elastomeric material and at least one textile reinforcement layer in alternating layers.

11. The multilayer tube according to claim 1, further comprising a metallic or thermoplastic wire which is wound helically inside said outer covering.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further characteristics and advantages of the disclosure will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the multilayer tube according to the disclosure, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

(2) FIG. 1 is a perspective view of a multilayer tube according to the disclosure;

(3) FIG. 2 is a longitudinal cross-sectional view of a portion of multilayer tube; and

(4) FIG. 3 is a longitudinal cross-sectional view of a portion of multilayer tube in a variation thereof.

DETAILED DESCRIPTION OF DRAWINGS

(5) With reference to the FIGS. 1-3, the multilayer tube according to the disclosure, generally designated by the reference numeral 10, comprises, in succession from the inside outward: a first layer 11 constituted by a tubular sheath that is at least externally corrugated and which defines the duct for the fluid, at least one second layer 12, which comprises an inner layer 13, chosen from between a rubberized fabric and an elastomeric material with textile reinforcement, which is arranged on the first layer 11, and an outer covering 14 which is arranged on the inner layer 13.

(6) The first layer is constituted by a fluorinated polymer, preferably PTFE, or in any case chosen from among FEP, MFA, PFA, PVDF, ECTFE, and PTFE.

(7) In addition, the first layer 11 is constituted by a tubular sheath which is smooth on the inner side for the passage of the fluid and is externally corrugated in a screw-like manner, so as to define helical peaks and troughs, while the second layer 12 is shaped internally like a female thread, so that it can be unscrewed from and screwed onto the first layer 11 and ensure a mechanical coupling and a seal against the relative axial movement between the two adjacent layers.

(8) The first layer 11 is preferably transparent or white. Alternatively, it can be made in different colors.

(9) The fabric of the inner layer 13 is constituted by a material that is preferably, but not exclusively, chosen among aramid, glass fiber, KEVLAR™ poly-para-phenylene terephthalamide, polyester, rayon and nylon.

(10) The same fabric of the inner layer 13 can be wound in a helix on the first layer 11 or, alternatively, it can have a tubular braided structure so as to form a sleeve covering the first layer 11. In such case the fabric can be braided.

(11) The outer covering 14 comprises at least one layer made of elastomeric material 15 and at least one textile reinforcement layer 16 in alternating layers. In the examples shown, there are three layers of elastomeric material 15 alternating with two textile reinforcement layers 16. The textile reinforcement layer 16 can be constituted by a combination of single threads, fabrics or reinforcement meshes. These are wound in a helix onto the inner layer 13, with areas of overlapping, and the elastomeric layers 15 are vulcanized in an autoclave in order to obtain a covering 14 in a single piece.

(12) The first layer 11 is preferably not subjected to surface cementation, or in any case it is not treated in any way in order to facilitate adhesion. Therefore, in this case the first layer 11 does not adhere to the inner layer 13, remaining independent of it.

(13) When during the production of the tube the inner layer is arranged on the first layer 11, it conforms to the shaping determined by the helical peaks and troughs. In this manner the second layer 12 obtains an internal shaping like a female thread, with which it interfaces with the screw-like outer shaping of the first layer 11.

(14) In a variation illustrated in FIGS. 3 and 4, the outer covering 14 also comprises a metallic or thermoplastic wire 17 (in other cases there can be more than one), wound in a helix inside the outer covering 14.

(15) Such wire 17 renders the tube more resistant to bending, thus preventing it from collapsing.

(16) Use of the multilayer tube, according to the disclosure, is the following.

(17) During installation of the tubes, the operator can easily cut the second layer 12 in a circular fashion with a cutter at a distance from the end which is equal to a portion of tube necessary to insert a connector.

(18) The cut portion of second layer 12, equal to the useful length for inserting the connector, is easily unscrewed from the first layer 11, because the friction is low, the cut piece being relatively short.

(19) The part of the first layer 11 without the covering of the second layer 12 has a screw-like outer shaping onto which a connector can be easily screwed by making the innermost layer 11 pass inside the tube-connector hole.

(20) In practice it has been found that the disclosure fully achieves the intended aim and advantages by providing a multilayer tube that can be easily and rapidly connected, with an excellent level of flexibility and of strength.

(21) In fact, by virtue of the fact that the inner layer is screw-shaped outside, it is perfectly coupled to the second layer, which is shaped like a female thread, thus creating a mechanical seal with it and so preventing the relative sliding between the two layers along the axis of the tube, and the two can also easily be separated during the operation of connecting and optional trimming at the ends, simply by unscrewing a portion of second layer.

(22) Furthermore, by virtue of the smooth inner surface of the first layer, the passage of fluid in the cavity is optimized, thus limiting the possibility that components of the fluid might stop on its surface and/or create turbulence inside it.

(23) In addition, the absence of metal fabrics in the tube appreciably contains its weight.

(24) The disclosure thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

(25) In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.