WO2008119395A1

WO2008119395A1 - Abrasive material transport pipe and process for its production

Info

Publication number: WO2008119395A1
Application number: PCT/EP2007/057488
Authority: WO
Inventors: Pierluigi Pelanda; Guido Lodi
Original assignee: Parker Itr S.R.L.
Priority date: 2007-04-03
Filing date: 2007-07-19
Publication date: 2008-10-09
Also published as: DE202007018475U1; ITMI20070679A1

Abstract

The abrasive material transport pipe (1) comprises a tubular body (2) of flexible material defining a cavity (4) into which a plurality of protection elements (3) project. The protection elements (3) comprise a plurality of plates, of which only a first face (6), facing towards said cavity (4), is free. The process for producing the abrasive material transport pipe (1) consists of wrapping a plurality of layers of flexible material about a mandrel. After wrapping a first layer (21) of flexible material about the mandrel (20), a support (22) to which a plurality of protection plates (3) are fixed is wrapped about the first layer (21), after which at least one other layer (24) of flexible material is applied onto these protection plates (3).

Description

ABRASIVE MATERIAL TRANSPORT PIPE AND PROCESS FOR ITS PRODUCTION

The present invention relates to a pipe for transporting abrasive materials and to a process for its production.

In industry, abrasive materials such as coal, powdered glass, various metals, etc. often require handling.

Traditionally these materials are handled by plastic and/or elastomeric material pipes, often connected to suction and/or propulsion systems.

However because of the intrinsic characteristics of the pipe constituent materials (i.e. plastic material) and of the transported materials

(which abrade the pipe within which they are transported), the pipe undergoes rapid deterioration and requires very frequent replacement; these pipes are usually replaced, for example, every week.

This results in high costs deriving from the purchase and storage of replacement pipes, machine downtime, and specialized personnel for making the replacement.

To overcome these drawbacks, plastic and/or elastomeric material pipes have been produced provided with a plurality of protection elements consisting of ceramic balls embedded in the pipe body.

However it has been observed that as these balls project from the inner surface of the tubular element to define a surface with numerous projections, during use the ceramic balls tend to be removed by the material flowing within the pipe; hence this pipe becomes abraded fairly rapidly. In this respect, it has been found that in this case the pipes have to be replaced every two/three weeks on average.

The technical aim of the present invention is therefore to provide an abrasive material transport pipe and a process for its production by which the stated technical drawbacks of the known art are eliminated.

Within the scope of this technical aim an object of the invention is to provide an abrasive material transport pipe which is very resistant, particularly when compared with traditional plastic and/or elastomeric material pipes, or with pipes of plastic and/or elastomeric material comprising protection elements.

Another object of the invention is to provide an abrasive material transport pipe in which the high costs deriving from the purchase and storage of replacement pipes, machine downtime, and specialised personnel for making the replacement are limited. Another object of the invention is to provide an abrasive material transport pipe provided on the inner surface of the pipe with protection elements which are fixed securely to the pipe such that the protection elements are not removed by the material transported by the pipe during its use. A further object of the invention is to provide a process for producing an abrasive material transport pipe which is simple, fast and economical.

The technical aim, together with these and other objects, are attained according to the present invention by an abrasive material transport pipe and a process for its production in accordance with the accompanying claims. Advantageously, the pipe of the present invention is able to transport abrasive products to be driven by suction and/or propulsion, and also products which require the absolute absence of electric charges, including of electrostatic type; for example the pipe of the invention is suitable for transporting coal.

Further characteristics and advantages of the invention will be more apparent from the description of a preferred but non-exclusive embodiment of the pipe and process of the invention, illustrated by way of non-limiting example in the accompanying drawings, in which: Figure 1 is a longitudinal section through the pipe of the invention;

Figure 2 is an inner view of the surface of the cavity of the pipe according to the invention;

Figure 3 is an enlarged longitudinal section through the pipe of the invention; Figure 4 is a partly sectioned perspective view of the pipe of the invention; and

Figure 5 shows the pipe during its production.

With reference to said figures, these show an abrasive material transport pipe indicated overall by the reference numeral 1. The pipe 1 comprises a tubular body 2 of flexible material such as plastic and/or elastomeric material; the tubular body 2 defines a cavity 4 into which a plurality of protection elements 3 project (during use, when the pipe is under working conditions).

The protection elements 3 comprise a plurality of plates which (when the pipe has been installed and is under working conditions) have only a first face 6, namely that facing the cavity 4, free whereas the lateral edges and at least a face opposite the first face 6 are embedded in the tubular body 2.

Advantageously, the surface of the first faces 6 of the plates 3 is substantially aligned with the surface 7 of the cavity of the tubular body. The plates 3 (Figure 2) are of hexagonal or polygonal plan shape and are formed of ceramic material such as sintered alumina.

Advantageously, the pipe of the invention also presents a steel reinforcement spiral 8 embedded in the tubular body 2.

Additionally, the pipe 1 also presents a copper spiral 9 to discharge electrostatic charges to earth; this is also embedded in the tubular body 2.

In a preferred embodiment, the pipe 1 comprises one, two or more reinforcement layers 11 , 12 embedded in the tubular body 2.

Each of these reinforcement layers 11 , 12 is formed from a fabric which internally and/or externally wraps the reinforcement spiral 8 and/or the copper spiral 9.

In this manner the pipe 1 is able to operate under pressure and under vacuum; the type of fabric defines the pressure and/or vacuum under which the pipe can operate safely, the fabric being in particular of polyester, nylon, glass fibres, aramid fibres, etc. Advantageously, the tubular body 2 is formed from a plurality of layers of plastic material (equal or different from one layer to another) superposed on each other.

The present invention also relates to a process for producing the abrasive material transport pipe. The process consists of wrapping about a mandrel 20 a plurality of layers of flexible material. Specifically, after wrapping a first layer 21 of flexible material (plastic and/or elastomeric material) about the mandrel 20, a support 22 to which a plurality of ceramic protection plates 3 are fixed (glued) is wrapped about the first layer, after which a second layer 24 of flexible material (plastic and/or elastomeric material) is applied onto said protection plates 3 to copenetrate the spaces 27 between the plates 3.

A further layer of flexible material 25 is then applied.

The support 22, consisting of a mesh of textile material or paper, is wrapped about the first layer 21 of flexible material (plastic and/or elastomeric material) to directly rest on said first layer 21.

A first fabric reinforcement layer 11 is applied to the layer 25.

The steel reinforcement spiral 8 and the copper spiral 9 are then wound.

A further fabric reinforcement layer 12 is applied to the spirals 8 and 9, then a layer which embeds the reinforcement layers 11 , 12 into the tubular body 2 is applied.

Afterwards, at least one further layer 26 of flexible material is applied as final covering for the pipe (plastic and/or elastomeric material).

When the pipe 1 is installed, the abrasive material transported through the pipe removes (in a short time) the layer 21 and the support 22

(mesh); hence during normal operation the pipe 1 presents the plates 3 with their lateral edges and one face embedded into the constituent plastic material of the tubular body 2, and with the face 6 (facing the cavity

4) free; in particular the free face 6 of the plate 3 is aligned with the surface 7 of the cavity 4. A pipe of the invention having the aforedescribed characteristics (tubular body, steel and copper spirals, fabric reinforcements and reinforcement plates) is described in detail below.

EXAMPLE The layer 21 of the pipe 1 (prior to installation) has a thickness of

0.5-4 mm and is formed of a black SBR blend of 65 ± 5 Shore A hardness.

It facilitates slippage and pressure sealing where internal socket connections are used.

As an alternative the layer 21 can be formed from an EPM blend particularly resistant to high temperatures and to aggressive chemical substances.

The support is formed of textile material or paper glued to the plates; it serves as a support for the plates during the pipe construction.

The plates are made of alumina oxide produced by sintering atomized powders of very high hardness (Mosh scale 9), high compactness (porosity 0), of hexagonal shape with sides 12 and 20 mm or polygonal shape with sides 10x20 or 20x20 mm, thickness 3 to 6 mm, with a surface treated to facilitate binding to the filling rubber of the layer 24.

The layer 24 (filling for the spaces between the reinforcement plates) has a thickness of 2-4 mm and is made of black BR/NR blend of 65 ± 5 Shore A hardness. It is particularly elastic and resistant to abrasion < 60 mm³.

As an alternative an EPDM blend particularly resistant to high temperatures and to aggressive chemical substances can be used. The reinforcement layer 11 is composed of cellulose or polyester or polyamide or aramid textile threads of count from 1000 to 4000 decitex coupled with blends suitable for binding to the filling blends laid at an angle from 45 to 60° in 1 or 2 or 3 layers.

The reinforcement spiral is of harmonic steel type B 1 UNI 3823 phosphate or zinc coated wire of diameter 1 to 5 mm. It ensures circularity of the pipe when bent, and also ensures good resistance to 0.8 bar vacuum.

The copper spiral is composed of 9-30 twisted tin-plated copper wires of diameter 0.10-0.30 mm to ensure dissipation of electrostatic charges and electrical continuity between the ends of the pipe/connection. The spiral filling layer (for embedding) is of 0.75-3 mm thickness and is formed of a black SBR blend of 65 ± 5 Shore A hardness. Alternatively, an EPDM blend particularly resistant to high temperatures and to aggressive chemical substances can be used.

The second reinforcement layer 12 is identical to the first reinforcement layer 11 in terms of nature, type and angle of the fabric, however it is suitably laid in a direction crossing the first.

The layer 26 is laid to protect the textile inserts; it has a thickness of 1.0-4.0 mm and is made from a black antistatic SBR blend (R < 2.0 MOhm/m) of 65 ± 5 Shore A hardness. It is particularly resistant to abrasion, atmospheric agents and ozone. Alternatively, an EPDM blend particularly resistant to high temperatures and to aggressive chemical substances can be used.

It was found that a pipe formed in this manner was able to transport abrasive material for many months without having to be replaced. It has been found that in practice that the pipe and process of the invention are particularly advantageous because they enable the useful life of the pipe to be substantially increased.

The pipe and process conceived in this manner are susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover all details can be replaced by technically equivalent elements.

In practice the materials used and the dimensions can be chosen at will according to requirements and to the state of the art.

Claims

1. An abrasive material transport pipe comprising a tubular body of flexible material defining a cavity into which a plurality of protection elements project, characterised in that, during use under working conditions, said protection elements comprise a plurality of plates, of which only a first face, facing towards said cavity, is free.

2. A pipe as claimed in claim 1 , characterised in that said plates have their lateral edges and at least a face opposite the first face embedded in the tubular body.

3. A pipe as claimed in one or more of the preceding claims, characterised in that the surface of the first faces of the plates is substantially aligned with the surface of the tubular body cavity.

4. A pipe as claimed in one or more of the preceding claims, characterised in that said plates are of hexagonal or polygonal plan shape.

5. A pipe as claimed in one or more of the preceding claims, characterised by being formed of ceramic material, preferably of sintered alumina.

6. A pipe as claimed in one or more of the preceding claims, characterised by presenting a reinforcement spiral, preferably of steel, embedded in said tubular body.

7. A pipe as claimed in one or more of the preceding claims, characterised by presenting, for discharging electrostatic charges to earth, a spiral, preferably of copper, embedded in said tubular body.

8. A pipe as claimed in one or more of the preceding claims, characterised by comprising at least one reinforcement layer embedded in said tubular body.

9. A pipe as claimed in one or more of the preceding claims, characterised in that said reinforcement layer is formed from a fabric.

10. A pipe as claimed in one or more of the preceding claims, characterised in that said fabric internally and/or externally wraps said reinforcement spiral and/or said spiral for discharging electrostatic charges to earth.

11. A pipe as claimed in one or more of the preceding claims, characterised in that said tubular body is formed of plastic material.

12.A process for producing an abrasive material transport pipe consisting of forming a plurality of layers of flexible material superposed on each other, characterised in that after forming at least a first layer of flexible material, a support on which a plurality of protection plates are fixed is wrapped about the first layer, after which at least one other layer of flexible material is applied onto said protection plates.

13.A process as claimed in claim 12, characterised in that when said support is wrapped about the first layer of flexible material, the support rests directly on the first layer of flexible material.

14.A process as claimed in one or more of claims 12 and onwards, characterised in that said support is a mesh preferably formed of textile material or paper.

15.A process as claimed in one or more of claims 12 and onwards, characterised by embedding in said tubular body a reinforcement spiral and/or a spiral able to discharge electrostatic energy to earth.

16.A process as claimed in one or more of claims 12 and onwards, characterised by embedding a reinforcement fabric in said tubular body.

17.A process as claimed in one or more of claims 12 and onwards, characterised in that said reinforcement fabric is embedded internally and/or externally onto said reinforcement spiral and/or said spiral able to discharge electrostatic charges to earth.

18.A process as claimed in one or more of claims 12 and onwards, characterised in that said reinforcement plates are of ceramic material, said material being of plastic and/or elastomeric material.

19.A process as claimed in one or more of claims 12 and onwards, characterised in that during use, the abrasive material transported through the pipe removes the first layer and the support.

20.An abrasive material transport pipe, characterised by being produced by a process claimed in one or more of claims 12-19.

21.An abrasive material transport pipe, characterised by comprising a layer of flexible material about which a support is wound to which a plurality of protection plates are fixed, on the protection plates there being applied at least one other layer of flexible material which at least partially copenetrates the spaces between the plates 3.