AU639890B2 - Tube useful for transporting fluids capable of varying its volume and in particular its length - Google Patents

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-68 COMPLETE SPECIFICATION

(ORIGINAL)

Class lIt. Clas Application *-Jumber: Lodged: a Complete Specification Lodged: Acceptrod: Kibiish ad: Pilority Related Art .Nirpe of Applicant: ATOCHEM 4airess of Applicant: La Def ense 10 4 8 Cours Mkhelet 92800 Puteaux, France Arlual Inventor: Address for' Service: MI CI-EL MALCOEFFE )RW WNAWWraemr Patent Trademark Attorneys 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: TUBE USEFUL FOR TRANSPORTING FLUIDS CAPABLE OF VARYING ITS VOLUME AND IN PARTICULAR ITS LENGTH the following statement is a full description of this invention, including the best metheld of performing it known to us rp S_ s csw 1 TUBE WHICH CAN BE USED FOR CONVEYING FLUIDS CAPABLE OF CHANGING ITS VOLUME AND ESPECIALLY ITS LENGTH The present invention relates to a tube which can be used for conveying fluids which, owing to their passage, are capable of reversibly and macroscopically changing the volume, and especially the length, of the tube.

It is known that standard and premium grades of gasoline cause swelling of objects based on polyamide 11 i (PA 11), polyamide 12 (PA 12) and also those based on polyamide 6 (PA 6) polybutylene terephthalate, polyacetal, etc.

In the case of PA 11 and of PA 12, various chemical agents cause these to swell; examples which may be mentioned are aromatic hydrocarbons such as benzene, toluene, xylene or styrene, diethanolamine at a concentration of 20 pure acetone, furfurol, methyl, ethyl and butyl alcohols, and glycerine. The swelling observed is reversible; however it should be noted that this reversibility is more or less rapid depending on the 4 vapour pressure of the fluid in question.

In motor vehicles it is found that the conduits, 11 especially polyamide-based, respon-_ole for conveying gasoline from the tank towards the carburettor dilate and in particular lengthen appreciably under the effect of gasoline containing added alcohol(s), so that the elongation of the conduit may attain approximately 5 of its initial length. Such an elongation is particularly 11I-- 2 i,.

ii ol~ r r r i u unfortunate because the conduit is no longer integral with the floor but droops under the floor under the effect of gravity greatly increasing the risks of tearing away when the vehicle takes to uneven terrain (potholes, ruts, "sleeping policemen", etc.). To overcome this disadvantage it is possible to increase the number of points of attachment of the conduit under the floor in order to limit the amplitude of the distancing of the tube relative to its initial position close to the floor. This solution lengthens the time for fitting the conduit to the vehicle, also entailing an extra cost due to the additional attachments needed.

The solution developed by the Applicant Company consists in employing a tube of such geometric configuration that it can absorb elastically a macroscopic deformation generated by an external physical and/or mechanical stress, whether continuous or otherwise. The tube according to the invention, employed for conveying fluids capable especially of reversibly and macroscopically changing its volume and especially its length, is characterized in that at least one part of the said tube can absorb elastically a deformation such as defined above.

The Applicant Company has focused its interest particularly on a tube such as described above in which, in addition, at least one section comprising at least one part capable of absorbing elastically a deformation such as defined above is approximately inscribe in a plane, i~trii~~ZiyLIC_1(-Y; 3 I's, fi whether the said section is deformed or not.

The tubes according to the invention may be simple smooth-walled tubes.

The part(s) capable of absorbing elastically a deformation such as defined above may have the shape of one or more lyres or a capital omega, or one or more turns.

The tubes according to the invention may also be at least partially ringed, and in particular the part(s) capable of absorbing elastically a deformation such as defined above may be ringed.

The ringed tubes or parts of tube can notably be such as those described in the specification and in the drawings of French Patent N 0 2 427 538 in the name of THOMSON-BRANDT. Among-the various plastics which can be employed for producing tubes according to the invention, preference is given to thermoplastics and/or thermoplastic elastomers.

Shaping of thermoplastic materials, whether elastomeric or otherwise, is easy: a simple heat treatment allows a rectilinear tube obtained, for example, by extrusion to acquire a more complex and permanent geometric configuration.

Among the usually encountered heat treatments applied to thermoplastic materials there may be mentioned the bending or shaping of a rectilinear tube at a sufficient temperature for it not to tend to return to its rectilinear position owing to its "plastic memory".

During the bending or shaping operation, heating of the tube may take place in an oven, using steam, oil or sand, or by circulating hot air, and the like.

-Ir i" j -o T T 11 4 To produce a tube wich is at least partially ringed, it is possible to employ the hot-shaping technique applied to a smooth-walled tube.

The materials of which a tube according to the invention consists may be chosen indiscriminately from the various groups of thermoplastic polymers. Polystyrene, polyvinyl chloride, polycarbonates, polyamides and acrylic resins may be mentioned as an example of a thermoplastic polymer.

o B Among thermoplastic materials, those based on polyamide are more particularly preferred.

Polyamides mean polymers resulting from the polycondensation of one or more amino acids such as aminocaproic, 7-aminoheptanoic, 11-aminoundecanoic, 12aminododecanoic and similar acids, of one or more lactams such as caprolactam, oenantholactam, dodecalactam, undecalactam, and the like, of one or more salts or mixtures of diamines such as hexamethylenediamine, dodecamethylenediamine, meta-xylylenediamine, bis-paminocyclohexylmethane, trimethylhexamethylenediamine and Sthe like with diacids such as isophthalic, terephthalic, adipic, azelaic, suberic, sebacic, dodecanedioic and similar acids, or mixtures of all these monomers, which leads to copolyamides.

Among these polyamides there will be mentioned very particularly: polyamide 11, obtained by polycondensation of ll-aminoundecanoic acid, 5 polyamide 12, obtained by polycondensation of 12-aminododecanoic acid or of dodecalactam, polyamide 12,12, obtained by copolycondensation of dodecamethylenediamine and dodecanedioic acid, and it copolyamides obtained by polymerization of the monomers referred to above.

The materials of which a tube according to the invention consists may also be chosen indiscriminately from the various groups of thermoplastic elastomers (TPE).

In general, among the thermoplastic elastomers j prominence is given to: 1 polymer mixtures often produced from polyolefins, \called olefinic thermoplastic elastomers (TPO) in this i case. By way of example there may be mentioned mixtures based on polypropylene and on a copolymer of ethylene, propylene and a diene such as isoprene or 1,3-butadiene

(EPDM);

block copolymers which have a sequential distribution of units consisting of rigid blocks and of flexible blocks: |I 1) Polystyrene-based block copolymers, that is to j say those in which the rigid phase consists of polystyrene sequences, it being possible £lr the flexible phase to consist of polybutadiene, polyisoprene or poly(ethylene-butylene) sequences.

2) Polyurethane-based block copolymers, which can be obtained by a combined reaction of a diol of high t 6 molecular weight, which forms the flexible sequence, with a diisocyanate and a diol of low molecular weight, which give rise to the rigid sequence.

3) Polyester-based block copolymers, in which the rigid sequence is a polyester such as, for example, polybutylene or polyethylene terephthalate, the said rigid sequences being copolymerized with flexible sequences consisting, for example, of a glycol of low molecular weight in combination with a poly(alkylene ether) glycol.

4) Block copolymers based on polyamide in the case of the rigid sequences and on flexible polyether sequences, also called polyetheramides. These block polyether-amides can result especially from the copolycondensation of polyamide sequences with reactive ends with polyether sequences with reactive ends, such as, among others: a) Polyamide sequences with diamine chain ends with polyoxyalkylene sequences with dicarboxylic chain ends.

b) Polyamide sequences with dicarboxylic chain ends with polyoxyalkylene sequences with diamine chain ends obtained by cyanoethylation and hydrogenation of alphasomega-dihydroxylated aliphatic polyoxyalkylene sequences called polyetherdiols.

c) Polyamide sequences with dicarboxylic chain ends with polyetherdiols, the polyetheramides obtained being, in this particular case, polyetheresteramides, particularly preferred by the Applicant Company.

The composition and the manufacture of such

C.

7 P O o polyetheresteramides have been described in French Patents No. 74/18,913 and 77/26,678 in the name of the Applicant Company and whose disclosure is incorporated in to the present description by reference.

In addition to thermoplastic polymers and/or thermoplastic elastomers (by themselves, mixed, or copolymerized), the material of which the tube according to the invention consists may contain various additives such as plasticizers, stabilizers to heat and to light, fillers such as glass or carbon fibres, pigments, and the like.

Another subject of the present invention is the use of a tube such as described above for conveying fluids which may be capable or incapable of changing its volume, especially its length, in a reversible and macroscopic manner (for example through a physicochemical and/or thermal action).

The solution proposed by the Applicant Company consists in fixing the tube in extension relative to the geometric configuration which it has when empty, if it is more particularly intended to receive fluids which make it dilate or swell, and in particular lengthen, but also if it is more particularly intended to receive fluids which make it contract.

Whatever the nature of the fluids conveyed and their effects on the volume, and especially the length, of the tube, the consequence of fixing the tube is that the spacial movement of the tube under the effect of the .1 "modifier" fluids will consist in this tube reverting towards or beyond its geometric configuration when empty.

:jThe most advantageous fixing consists in applying to a tube according to the invention a modular stress such that it compensates as accurately as possible for the volume change of the tube due to the "modifier" fluid conveyed.

In the case of a tube according to the invention which is fixed in extension, and of which additionally at least one section comprises at least a part capable of Sabsorbing elastically a deformation such as defined above, Sif the said section is approximately inscribed in a plane the spacial change of said section will take place solely in this plane.

:j Such a tube, fixed in extension, may be advantageously employed as a conduit for gasoline: the part under j the floor which comprises at least one section inscribed approximately in a plane remains close to and parallel to the floor because its spacial change due to the "modifier" fluid takes place in parallel to the floor.

There is no need to multiply the number of tube fastening points, which are generally distributed uniformly along the tube and approximately 200 mm apart from each other. Care must only be taken to ensure that the fastenings which are in a part of the tube where an elastic deformation is produced neither interfere with nor prevent the movements of the tube.

9 Fastenings which are employed may be, for example, free clips, that is to say those allowing the tube to slide sideways.

The part(s) which may be subjected to an elastic deformation can be optionally integrally fastened to a spring or springs, judiciously placed and intended to accelerate the lengthwise changes in the tube under the effect of the fluids conveyed.

In order to illustrate the present invention, a description of some examples of embodiment has been given below, with reference to the accompanying drawings which show various geometric configurations of tubes according to the invention.

The smooth-walled tubes shown in Plates I to IV, enclosed herewith, have the following dimensions: length: approx. 2.5 m outer diameter: 8 mm inner diameter: 6 mm.

They were made from the following materials: Sample i: polyamide 11, black-coloured, stabilized to heat, whose melting point is between 183 and 187 0 C, and containing 6 of plasticizer.

Sample ii: polyamide 11, black-coloured, stabilized to heat and to light, whose melting point ranges between 178 and 184 0 C, and containing 12 of plasticizer.

Sample iii: polyamide 12, black-coloured, stabilized to heat and to light, whose melting point ranges il; i 10 between 173 and 177 0 C, and containing 6 of plasticizer.

Sample iv: polyamide 12, black-coloured, stabilized to heat and to light, whose mel-ing point ranges between 168 and 174 0 C, and containing 12 of plasticizer.

In the case cf Samples i, ii, iii and iv, the three geometric configurations of the tube in accordance with the invention, shown in Figures 1 of Plates I to III were obtained by oven shaping at 140-150 0

C.

Figure 1 of Plates I to III shows a tube according to the invention, which is approximately inscribed in a plane, in this case the plane of the sheet.

The part of the tube which can absorb a macroscopic deformation elastically has the shape of a capital o.nega (or of a lyre) in the case of Plates I and II.

The average diameter of the omega is 12 cm and its two arms are approximately contiguous.

The tube of Plates I and II is fitted with two clips (a and one is stationary and clamped onto the shorter rectilinear part of the tube, the other is free and fixed at the distance equal to 1.50 m from the other end of the tube.

The total length of the two rectilinear parts of the tube is equal to approximately 2 m.

The tube shown in Plate II is also fitted with a stay spring joining the two arms of the omega.

In the case of the tube shown in Plate III the portion which can absorb an elastic deformation has the i 1 11 shape of a loop or turn whose diameter is substantially equal to 15 cm.

The tube of plate III is fitted with two clips (a and one is stationary and clamped onto the shorter rectilinear part of the tube, the other is free and fixed at a distance equal to approximately 1.50 m from the other end of the tube.

The total length of the two rectilinear parts of the tube is equal to approximately 2 m.

The tubes according to the invention which are shown in Figures 1 of Plates I to III have been fixed in extension with the aid of two couplings (c and attached to their ends (in conditions which are identical for each of the tubes of Plates I to with an elongation corresponding to approximately 4 of the initial length of the tube (Figures 2 Plates I to III). The Applicant Company has employed standard clamp ring couplings and quick-connect couplings.

In addition to the clips (a and the tubes of Plates I to III are fitted with clips which are uniformly distributed and approximately 200 mm apart from each other.

Thus, in the case of the tube of Plate I, fixed in extension (Figure the spacing between the two arms of the omega is approximately 10 cm.

In the case of the tube of Plate III, fixed in extension (Figure the loop or turn takes an oblong shape; its length (dl) is equal to approximately 12 cm and .1 12 its width (d 2 to approximately 10 cm.

Gasoline to which 15 of methanol has been added is then circulated inside the tubes fixed in this manner.

Figure 3 of Plates I to III corresponds to the geometric configuration which the tube adopts under the effect of this fluid. In the case of samples i, ii, iii and iv, the results obtained are identical.

0 4 1 o a 0 0i 0 3 4 0e 4

Claims (9)

1. Tube made of thermoplastic polymer attached beneath a floor of a vehicle when used in conveying aromatic and/or aliphatic hydrocarbons capable of reversibly and macroscopically deforming the tube by changing its volume and especially its length as a result of chemical interaction between said thermo- plastic polymer and said aromatic and/or aliphatic hydrocarbons, characterized in that tube comprises between two points along the tube length, at least one macroscopic deformation absorbing portion which has an initially preformed non-inear shape, and is fixed in extension between those two points, said deformation absorbing portion being elastically yieldable substantially to its initially preformed non-linear shape in response to a deformation resulting from the aromatic and/or aliphatic hydrocarbons flowing in the tube.

2. Tube as claimed in Claim 1, characterized in that at least one section of the said tube is approximately inscribed in a plane; and in that said section comprises at least one deformation-absorbing portion.

3. Tube as claimed in Claims 1 or 2, characterized in that the deformation- absorbing portion has the shape of one or more lyres or omegas.

4. Tube as claimed in Claim 1 or 2, characterized in that the deformation- absorbing portion has the shape of one or more loops. S

5. Tube as claimed in Claims 1 or 2, characterized in that the deformation- absorbing portion is ringed.

6. Tube as claimed in any one of Claims 1 to 5, characterized in that it is based on polyamide, copolyamide or a polyamide-based mixture and advantageously based on PA 11 and/or PA 12 and/or PA 12,12.

7. Tube as claimed in any one of Claims 1 to 5, characterized in that it is based on block copolymer(s) based on 'TT C i j 14 polyamide and/or based on polyester, and advantageously based on polyetheresteramide.

8. Tube as claimed in Claims 6 or 7 characterized in that it is based on thermoplastic mixtures and/or copolymers and thermoplastic elastomers.

9. Tube as claimed in any one of Claims 1-8 characterized in that it is a conduit for gasoline to which one or more alcohols have been added. DATED this 4th day of January, 1993 ATOCHEM WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA C 1<