CA1227313A - Flexible tubing and method of manufacturing same - Google Patents
Flexible tubing and method of manufacturing sameInfo
- Publication number
- CA1227313A CA1227313A CA000515733A CA515733A CA1227313A CA 1227313 A CA1227313 A CA 1227313A CA 000515733 A CA000515733 A CA 000515733A CA 515733 A CA515733 A CA 515733A CA 1227313 A CA1227313 A CA 1227313A
- Authority
- CA
- Canada
- Prior art keywords
- core
- coating
- reinforcing material
- tubing
- extruder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
Abstract of the Disclosure Reinforced flexible tubing of thermoplastic material is provided. The tubing includes a tubular core of thermo-plastic material having on the outer surface thereof a multi plicity of contiguous formations integral with the core, the formations defining valleys therebetween, reinforcing material disposed on the outer surface of the core in intimate contact with the surface of the core and a coating of thermoplastic mate-rial covering the outer surface of the core and the reinforcing material, the thermoplastic material of the coating being directly and intimately bonded to the thermoplastic material of the core. Also provided is an apparatus for manufacturing rein-forced flexible tubing of thermoplastic material. The apparatus includes a core supply for supplying a flexible tubular core, a reinforcing material supply device for supplying reinforcing material to the outer surface of the core and an extruder arranged to extrude a coating of thermoplastic material onto the outer surface of the core and the reinforcing material, the extruder being adapted to enable a positive air pressure differ-ential to be applied between the exterior and interior of the coating around the core during extrusion of the coating.
Further provided is a method for manufacturing reinforced flex-ible tubing of thermoplastic material which includes providing a flexible tubular core of thermoplastic material, supplying rein-forcing material to the surface of the core and extruding, by means of an extruder, a thermoplastic coating on the outer sur-face of the tubular core and the reinforcing material while creating a positive air pressure differential between the exterior and interior of the coating in the extruder during extrusion to urge the coating into intimate contact with the core and the reinforcing material. The reinforced tubing of the invention permits a reduction of up to 30% of the material used to form the coating while maintaining the resistance to bursting.
Further provided is a method for manufacturing reinforced flex-ible tubing of thermoplastic material which includes providing a flexible tubular core of thermoplastic material, supplying rein-forcing material to the surface of the core and extruding, by means of an extruder, a thermoplastic coating on the outer sur-face of the tubular core and the reinforcing material while creating a positive air pressure differential between the exterior and interior of the coating in the extruder during extrusion to urge the coating into intimate contact with the core and the reinforcing material. The reinforced tubing of the invention permits a reduction of up to 30% of the material used to form the coating while maintaining the resistance to bursting.
Description
~ ., L ')--4 /
~ ~273~
FL!EXIBLE TUBING AND
METHOD OF MANUFACTURING SAME
Background of the Invention Field of the Invention The present invention relates to reinforced flexible tubing of thermoplastic material and, more particularly, to rein-forced flexible tubing having high resistance to bursting.
- The present invention also relates to a method of manu-facturing flexible tubing of thermoplastic material.
Description of the Prior ~rt It is known to form a plastic tube, ~or example, by extrusion through a circular die, to reinforce that tube by applying a reinforcing material such as a textile or a metallic material, normally in braid or lap form, over the exterior sur-face thereof, and to apply a second (outer) tube, generally by extrusion over the inner tube of the reinforcing material. Pre-ferably, the outer tube is applied over the inner tube and the reinforcincJ material while the inner -tube is still warm from its own formation, which is generally by extrusion, so that the mate-rials of the inner and outer tubes can blend together and trap the reinforcing material therebetween. It is desirable to en-sure that the outer tube does adequately bond to the inner tube in order to provide for sufficient peel strength of the finished tubing and it is known to apply substances such as adhesives and bonding agents to the exterior surface of the inner tube to assist in the bonding o~ the outer tube there~o. Problems some-times arise with known reagents and misbonding occurs, in which event the inner and outer tubes are often separated from one an-other with th~ reinforcing material being bonded to neither the inner nor outer tube which reduces the strenqth and thas the 3Q ability to withstancl internal pre 5S ure.
~r,,~
Summa'ry of the Invention According to the invention, there is pro~Jided rein-forced flexible tubing of thermoplastic material comprising:
- a) a tubular core of thermoplastic material ha-~Jingon the outer surface thereof a multiplicity of contiguous forma-tions integral with said core, said formations de~ining valleys therebetween;
b) reinforcing material disposed on said outer sur-face of said core in intimate contact with said surface of said core; and c) a coating of thermoplastic material covering said outer surface of said core and said reinforcing material, said thermoplastic material of said coating being directly and intimately bonded to said thermoplastic material of said core.
According to another aspect of the inven-tion, there is provided a method for manufacturing reinforced flexible tubing of thermoplastic material comprising the steps of:
a) providing a flexible tubular core of thermo-plastic material;
b) supplying reinforcing material to the surface of said core; and c) extruding, by means of an extruder, a thermo-plastic coating on the outer surface of said tubular core and said reinforcing material while creating a positive air pressure differential between the exterior and interior of said coating in said extruder during extrusion to urge said coatin~ into intimate contact with said core and said reinforcing material.
~rief Description of the Drawings The present invention will be further described with reference to the followin~ drawings which are merely illustra-tive of the inven~ion and are not intended to limit the inven-tion .
,7~3~3 Figure 1 is a prospective, partly-cut awa~ vir--,/ of tub-ing according to the present invention;
Figure 2 is a transverse cross-section of tubing similar to that shown in Figure 1 but having more formations on the inner tube;
Figure 3 is a prospective, partly-cut awa~ vie~l o tub-ing of another embodiment of the present invention;
Figure 4 is a schematic diagram illustratinc3 the apparatus used in practising the invention;
Figure 5 is a sectional plan of an extruder formin-~
part of an embodiment of the apparatus;
Figure 6 is a transverse cross-section of an extrusion die useful in an embodiment of the apparatus;
Figure 7 is a sectional plan view of nip rollers use-ful in an embodiment of the apparatus;
Figure 8 is a -transverse cross-sectional view of tub-ing of an embodiment of the present invention; and Figure 9 is a ~ransverse cross-sectional ~iew of tub-ing of an embodiment of the present invention.
Description of the Prefexred embodiments Referring to Figures 1-3, reinforced flexibl~ tubin~ 1 has a tubular core 2 of thermoplastic material havinct a multi-plicity of contiguous formations 3 integral with the core. The formations 3 define valleys, each of which contains (Fic~ure 1) or is bridged by (Flgure 3) reinforcinct material 4. E~truded over and covering core 2 and reinForcinc~ material 4 is coatinc3 5 of thermoplastic material.
The out~r surface core 2 is formed with contic3uous formations 3, such as, for example, ridctes, ribs or undulations.
Preferahly, th~ formations comprise a series o~ rid~3es or rihs 7~3 defining the valleys therebetween and, mos-t preferably, th~
formations comprising a series of ridges which run longitudin-ally of the core 2 so that the ridges 3 are parallel to the main central axis of core 2. When a series of ribs or ridges are pro-vided, it is convenient for the valle~s defined therebet~/een to ~73~3 be V-shaped in cross-section, the ridges or ribs thus bein~3 cor-respondingly tapered from their base. It is, howe~er, 005sible to provide ribs or ridges having other shaped cross-sections such as trapezoidal cross-section. Where a trapezoidal cross-section is used, the shortest side of the trapezoidal cross-seetion is preferably adjacent to the outer surface of core 2.
The provision of the aforementioned formations increases the external surface area for a given outer diameter of core 2.
Tubular core 2 may be formed of any suitable thermo-plastic material. A preferred thermoplastic material for form-ing core 2 is polyvinyl chloride. Tubular core 2 may be formed of an anti-static thermoplastic material where anti-static pro-perties are required in the final product, such as in some types of tubing for medical purposes. Tubular core 2 havincJ forma-tions 3 on the outer surface thereof is preferably ~ormed by extrusion.
The reinforcing material 4 disposed on the outer sur-face of core 2 may be comprised o-E, for example, a textile mate-rial, such as yarn or thread, or a metallic material, such as wire. A kextile yarn, such as polyamide or polyester yarn, is preferred. For many tubing constructions, a yarn size of 1100 cdecitex gauge is suitable. Other yarn sizes can be selected, depending on the size of tubin~ and the reinforcement re~uired.
The reinforcing material ~ ma~ be dispased on the outer surface of core 2 in lapped or braided fashion, for example in criss-cross fashion~ ~hen reinforcin~ material ~ is in lapped or braided form, it is preferable that a pluralit~ o~, ~or example, textile yarns be disposed on the core to procluce the braid effect wlth half the reinforcin~3 material runnill~ in a spaced apart, somewhat clockwise clirection ancl the otller h~lr ~73~3 running in a spaced apart, somewhat counterclocl~,Jis~ r--~tion, the yarns crossing but leaving generally diamond-shape~ spaces therebetween. However, if core 2 has the aforementioned longi-tudinally disposed ribs or ridges, reinforcing material 4 ma~,~
also be conveniently placed along the length o-f valle~s ~ ned thereby, thus increasing the longitudinal as well as hoop strength.
A coating 5 of thermoplastic material covers reinforc-ing material 4 and tubular core 2. The thermoplastic material of coating 5 is generally similar to or compatible with that used for tubular core 2. Preferably, coating 5 is of the same thermoplastic material as core 2. ~lost pre$erably, both tubular core 2 and coating 5 are polyvinyl chloride. ~hen both the tubular core and coating are of polyvinyl chloride, the finished tube is usable over a temperature range of at least about -20 C
to ahout 65C.
The thermoplastic material of coating 5 is directl~
and intimately bonded to the thermoplastic material of the core
~ ~273~
FL!EXIBLE TUBING AND
METHOD OF MANUFACTURING SAME
Background of the Invention Field of the Invention The present invention relates to reinforced flexible tubing of thermoplastic material and, more particularly, to rein-forced flexible tubing having high resistance to bursting.
- The present invention also relates to a method of manu-facturing flexible tubing of thermoplastic material.
Description of the Prior ~rt It is known to form a plastic tube, ~or example, by extrusion through a circular die, to reinforce that tube by applying a reinforcing material such as a textile or a metallic material, normally in braid or lap form, over the exterior sur-face thereof, and to apply a second (outer) tube, generally by extrusion over the inner tube of the reinforcing material. Pre-ferably, the outer tube is applied over the inner tube and the reinforcincJ material while the inner -tube is still warm from its own formation, which is generally by extrusion, so that the mate-rials of the inner and outer tubes can blend together and trap the reinforcing material therebetween. It is desirable to en-sure that the outer tube does adequately bond to the inner tube in order to provide for sufficient peel strength of the finished tubing and it is known to apply substances such as adhesives and bonding agents to the exterior surface of the inner tube to assist in the bonding o~ the outer tube there~o. Problems some-times arise with known reagents and misbonding occurs, in which event the inner and outer tubes are often separated from one an-other with th~ reinforcing material being bonded to neither the inner nor outer tube which reduces the strenqth and thas the 3Q ability to withstancl internal pre 5S ure.
~r,,~
Summa'ry of the Invention According to the invention, there is pro~Jided rein-forced flexible tubing of thermoplastic material comprising:
- a) a tubular core of thermoplastic material ha-~Jingon the outer surface thereof a multiplicity of contiguous forma-tions integral with said core, said formations de~ining valleys therebetween;
b) reinforcing material disposed on said outer sur-face of said core in intimate contact with said surface of said core; and c) a coating of thermoplastic material covering said outer surface of said core and said reinforcing material, said thermoplastic material of said coating being directly and intimately bonded to said thermoplastic material of said core.
According to another aspect of the inven-tion, there is provided a method for manufacturing reinforced flexible tubing of thermoplastic material comprising the steps of:
a) providing a flexible tubular core of thermo-plastic material;
b) supplying reinforcing material to the surface of said core; and c) extruding, by means of an extruder, a thermo-plastic coating on the outer surface of said tubular core and said reinforcing material while creating a positive air pressure differential between the exterior and interior of said coating in said extruder during extrusion to urge said coatin~ into intimate contact with said core and said reinforcing material.
~rief Description of the Drawings The present invention will be further described with reference to the followin~ drawings which are merely illustra-tive of the inven~ion and are not intended to limit the inven-tion .
,7~3~3 Figure 1 is a prospective, partly-cut awa~ vir--,/ of tub-ing according to the present invention;
Figure 2 is a transverse cross-section of tubing similar to that shown in Figure 1 but having more formations on the inner tube;
Figure 3 is a prospective, partly-cut awa~ vie~l o tub-ing of another embodiment of the present invention;
Figure 4 is a schematic diagram illustratinc3 the apparatus used in practising the invention;
Figure 5 is a sectional plan of an extruder formin-~
part of an embodiment of the apparatus;
Figure 6 is a transverse cross-section of an extrusion die useful in an embodiment of the apparatus;
Figure 7 is a sectional plan view of nip rollers use-ful in an embodiment of the apparatus;
Figure 8 is a -transverse cross-sectional view of tub-ing of an embodiment of the present invention; and Figure 9 is a ~ransverse cross-sectional ~iew of tub-ing of an embodiment of the present invention.
Description of the Prefexred embodiments Referring to Figures 1-3, reinforced flexibl~ tubin~ 1 has a tubular core 2 of thermoplastic material havinct a multi-plicity of contiguous formations 3 integral with the core. The formations 3 define valleys, each of which contains (Fic~ure 1) or is bridged by (Flgure 3) reinforcinct material 4. E~truded over and covering core 2 and reinForcinc~ material 4 is coatinc3 5 of thermoplastic material.
The out~r surface core 2 is formed with contic3uous formations 3, such as, for example, ridctes, ribs or undulations.
Preferahly, th~ formations comprise a series o~ rid~3es or rihs 7~3 defining the valleys therebetween and, mos-t preferably, th~
formations comprising a series of ridges which run longitudin-ally of the core 2 so that the ridges 3 are parallel to the main central axis of core 2. When a series of ribs or ridges are pro-vided, it is convenient for the valle~s defined therebet~/een to ~73~3 be V-shaped in cross-section, the ridges or ribs thus bein~3 cor-respondingly tapered from their base. It is, howe~er, 005sible to provide ribs or ridges having other shaped cross-sections such as trapezoidal cross-section. Where a trapezoidal cross-section is used, the shortest side of the trapezoidal cross-seetion is preferably adjacent to the outer surface of core 2.
The provision of the aforementioned formations increases the external surface area for a given outer diameter of core 2.
Tubular core 2 may be formed of any suitable thermo-plastic material. A preferred thermoplastic material for form-ing core 2 is polyvinyl chloride. Tubular core 2 may be formed of an anti-static thermoplastic material where anti-static pro-perties are required in the final product, such as in some types of tubing for medical purposes. Tubular core 2 havincJ forma-tions 3 on the outer surface thereof is preferably ~ormed by extrusion.
The reinforcing material 4 disposed on the outer sur-face of core 2 may be comprised o-E, for example, a textile mate-rial, such as yarn or thread, or a metallic material, such as wire. A kextile yarn, such as polyamide or polyester yarn, is preferred. For many tubing constructions, a yarn size of 1100 cdecitex gauge is suitable. Other yarn sizes can be selected, depending on the size of tubin~ and the reinforcement re~uired.
The reinforcing material ~ ma~ be dispased on the outer surface of core 2 in lapped or braided fashion, for example in criss-cross fashion~ ~hen reinforcin~ material ~ is in lapped or braided form, it is preferable that a pluralit~ o~, ~or example, textile yarns be disposed on the core to procluce the braid effect wlth half the reinforcin~3 material runnill~ in a spaced apart, somewhat clockwise clirection ancl the otller h~lr ~73~3 running in a spaced apart, somewhat counterclocl~,Jis~ r--~tion, the yarns crossing but leaving generally diamond-shape~ spaces therebetween. However, if core 2 has the aforementioned longi-tudinally disposed ribs or ridges, reinforcing material 4 ma~,~
also be conveniently placed along the length o-f valle~s ~ ned thereby, thus increasing the longitudinal as well as hoop strength.
A coating 5 of thermoplastic material covers reinforc-ing material 4 and tubular core 2. The thermoplastic material of coating 5 is generally similar to or compatible with that used for tubular core 2. Preferably, coating 5 is of the same thermoplastic material as core 2. ~lost pre$erably, both tubular core 2 and coating 5 are polyvinyl chloride. ~hen both the tubular core and coating are of polyvinyl chloride, the finished tube is usable over a temperature range of at least about -20 C
to ahout 65C.
The thermoplastic material of coating 5 is directl~
and intimately bonded to the thermoplastic material of the core
2 and reinforcing tnaterial 4 is securely entrapped between core 2 and coating 5. This direct intimate bonding of the material of coating 5 to the outer surface of core 2 may prefs~rably he achieved by extruding coating S over cor~ 2 and rein~orcinc3 mat~-rial 4 with a positive air pressure diEferential bet~een the exterior and in-terior of the coating, as will be described in ~le-tail hereinafter with regard to the method oF the invention.
Often the coating of the tubing of the present inven-tion does not have a smooth surface, this }-eing particularly so when the material o~ the coatincl is extruds~d under pressure, an~' in general the outer surfac~ of the coatinc3 will follow the con-tours of the formatic>ns oE the S orS~ ancl~or the rS~in~orcins~3 n~S-~-
Often the coating of the tubing of the present inven-tion does not have a smooth surface, this }-eing particularly so when the material o~ the coatincl is extruds~d under pressure, an~' in general the outer surfac~ of the coatinc3 will follow the con-tours of the formatic>ns oE the S orS~ ancl~or the rS~in~orcins~3 n~S-~-
3~3 rial. Tubing of the p~esent invention havinc7 an outer su-- a-r which is not smooth affords advantages in the coiling there3f.
This is because tubing having a smooth outer surface ten-ls to stick to itself, especially with smooth polyvinyl chloride sur-faces, and this causes problems in automatic coiling wnich do not oceur with tubing of the present invention having a non-smooth surface.
If it is desirous to provide tubing of very high strength, reinforcing material may be applied on the outer sur-face of the coating, and a second coating applied thereover asshown in Fig. 9. The tubing thus formed includes a tubular core 2 having the aforementioned Eormations 3, reinforcing material 4A on the outer surface of tubular core 2, a coating 5A applied over the core and its reinforcing material ~, reinforcing mate-rial 4~ on the outer surface of the first coating and a second coating 5B applied over the first coating 5~ and its association reinforcing material 4B. The first and second coatings are applied so as to entrap the reinforcing materials between the core and first coating, and first and second coatings, respec-tively. The thermoplastic material of the first coating isdirectly and intimately bonded to the thermoplastic material of the core and the thermoplastic material of the second coating is direetly and intimately bonded to -the thermoplastic of the outer surface of the first coating.
The outer surface of this second coating may be smooth or non-smooth, although any tube produced in the aforementioned manner greatly reduces the interface bond stress sincc tne ~lc:;-ing shear load on the interface between the su~strate and the subsequent layers is spread over a large percentacJe o~ the resultant wall thickness of the whole tubing thereby rcducing the necessity for high artificial bond strength ~f cour~e, further layers of reinforciny material and thermoplas,ic mate-rial may be provided as required for even greater strenyth.
A further embodiment of the present invention is la_ tubing of ribbon-like form as shown in Fig. 8. Such tubin~ is substantially flat with the volume of the inside of the core be-ing substantially zero and contains subs-tantially no air within the inner part of the tubing when not in use. The tubing is cap-able of assuming a tubular form by introduction of internal fluid pressure. Such flattened tubing may be used as hosepipe, being sel~ draining, by virture of the elastic memory of the material for the ribbon-like form. This tubing is more easily formed into a roll and occupies less space for storage than con-ventional round tubing.
The ridges and valleys provide an additional function in this flat embodiment in that they act as hinge-like parts, allowing the hose to readily assume a traditional shape under internal pressure. When the pressure is removed, the hose re-turns to a substantially completely flat profile, ~ue to -the elastic memory of the tubing urging evacuation of the fluid with-in the tubin~.
The present invention generally enables a recluction of up to 30% of the material usecl to form the second tube in com-parison ~ith prior art composite tubinq and still is capable o^
achieving the same resistance to bursting as the conventional tubing. For example, fully flexible polyvinyl chloride tubing according to the present invention can be produced havin~ an overall thickness of no more than about 3 mm and an inside dia-meter of up to about 19 mm, with a capa~ility of working pres-sures as high as ~0 BAR at 20 C.
The excellent fle~.ibilit~y of the tu~in~ of th~ ?res~n_invention is high due to the need for less material or a gi-~-n strength.
The apparatus for manufacturing flexible reinforced tubing of the present comprises a core supply for suppl~ing a flexible tubular core, a reinforcing material suppl~ device for supplying at least one reinforcing material to the outer sllrface of the core and an extruder arranged to extrude a tubular coat-ing of thermoplastic material onto the outer surface of the core in the reinforcing material, the extruder being adapted to en-able a positive air pressure differential to be applied between the exterior and the interior of the coating around the core dur-ing extrusion of the coating.
The method o~ manufacturing flexible reinforced tubing of the present invention includes providing a flexible tubular core of thermaplastic material, supplying reinforcing material to the surfac~ of the core and extruding, by means of an extruder, a thermoplas~ic coating on the outer surface of the tubular core while creating a positive air pressure differential between the exterior and interior of the coating in the extruder during extrusion to urge the coating into intrinsic contact with the core and the reinforcing material. This positive air pres-sure differential during extrusion causes a ~ond to form directly bet~een the core and the coating.
Prefera~ly, the exterior of the coatin~ is at atmos-pheric pre5sure, and a vacu~lm is applied ta the interior of the coating as it is extruded. The coating is suitably extruded as a tube uni~ormly spaced ~rom the surface o~ the core, the vacuum drawinq the coatlng down onto the core while the coating is still in a plastic state.
_g_ ~7~1~
~ he core supply~ may be a reel, but is preferably an-other plastics extruder, continuousl~ forminy a tubular cDre which is cooled in water before passing through the winding d--vice. The reinforcing material suppiy de~Jice is preferably arranged to apply a plurality of reinforcing threads, half the thread running in the opposite direction to the other half.
The apparatus and method are capable of producing tub-ing having typically one third less material than con~entional tubing of the same general structure, internal diameter and burst pressure. The amount of tubing which has to be discarded through bond failure is substantially reduced and higher produc-tion speeds can be achieved.
The apparatus, shown in Figure 4, incluces a first extruder 11 which is a conventional screw feed extruder receiv-ing -thermoplastic material, such as polyvinyl chloride, in the form of granules. The arrangement of the granule feed hopper and feed screw barrel is conventional and these parts are there-fore not shown in de-tail, only a part of the barrel being shown.
The granules are melted and the molten thermoplastic material is forced through an annular die to extrude a tubular core 2, pre-ferably having an external surface consisting of longitudinal ridges and valleys of generally triangular configuration around the tube~ Dies suitable for extruding tubular core 2 are des-cribed in further detail hereinafter with re~ard to Figure 6.
The core 2 is preferably extruded at a temperature of about 140 to 150 C and at a linear speed of about 2000 ft/hr (170 mm/s) and passes through a cooling bath 13 containing a flow of cool-ing water. The cooling bath 13 cools the core ~ to about 70 C
before it reaches a reinforcing material supply, such as winding device 1~ for the application of reinforcing material. ~71ndin~ device 14 is CO,?s~
prised of two contra-rotating drums 14A and 14B, each OL ~Jnic--.
contain a plurality of reels 15 of reinforcing material. Th~
reinforcing material may be comprised of, for example, a te~.tile material, such as yarn or thread, or a metallic ~aterial, such as wire. The reels are arranged to feed the reinforcing mate-rial to the core under a very light tension and spaced apart so as to produce a braided effect, the yarns crossiny but leaving generally diamond-shape spaces therebetween.
The core with the reinforcin~ material thereon passes from winding device 14 into a second eY~truder 16 of similar general configuration to the first extruder 11. The coating material is a thermoplastic material, preferably a material which is similar to or compatible with that used for the core.
Most preferably both the core and the coating material care pol~
vinyl chloride. The coating material is supplied to an annular die which is described hereinafter in more detail with reference to Fig. 5. A vacuum pump 17 is connected to the extruder 16 by means of a vacuum pipe 18. The coated core passes through a second cooling bath 19 whose lenyth, coolant flow rate and tem-perature are selected to reduce the tempera~ure oE the coatinc3 from the extrusion temperature, which may be from about 1~0 ~o 150 C, to a suitable temperature to permit manual handlir.g of the tube, for example, forming into rolls such as on a reei 10.
Referring to Fig. 5, the extruder comprises an elon-gated screw 20 which drives the molten thermoplc~stic coatîng material into the extruding head 21. Elead 21 comprises a ~wo part extruding tool 22, havin~ an outer part 22~ containin~ a frusto-conical bore ?2B therethrougtl an~i a ~enerally rus~o-conical inner part 72C whose conical sur~ce contains all an{31e ~ ~ ~ 7 ~ 1t~
smaller than that contained by the surface of the ;~Gre~ 22~ ,einner part 22C has a cylindrical bore 22D therethrougn, 'h-e di--meter of whieh is larger than -the external diameter of .ne co e 2 with the reinforcing material wound onto the surface thereo so that the prevailing gas pressure at the rear face 22E o. the inner part 22C is substantially the same as that of the opposite end of the bore 22D.
The rear faee 22E is attached to one end of a tubular vaeuum ehamber 23 whieh is in turn attached to an adjusting ring 24 whieh is externally serew-threaded and screws into a corres-pond.ingly-threaded soeket 25 in the body of extruding head 21.
Rotation of -the adjusting ring 24 thus moves the inner part 22C
of the extruding tool relative to outer part 22A whieh in turn alters the thiekness of the eoating extruded.
A vaeuum eonnector piece 26 extends a~ially from adjusting ring 24 and has a bore 27 therethrough whieh eommuni-cates with the interior of vaeuum 23 and with vaeuum tube 28 whieh is eonneeted by flexible hose 8 to vaeuum pump 7 (s~e Fi~.
This is because tubing having a smooth outer surface ten-ls to stick to itself, especially with smooth polyvinyl chloride sur-faces, and this causes problems in automatic coiling wnich do not oceur with tubing of the present invention having a non-smooth surface.
If it is desirous to provide tubing of very high strength, reinforcing material may be applied on the outer sur-face of the coating, and a second coating applied thereover asshown in Fig. 9. The tubing thus formed includes a tubular core 2 having the aforementioned Eormations 3, reinforcing material 4A on the outer surface of tubular core 2, a coating 5A applied over the core and its reinforcing material ~, reinforcing mate-rial 4~ on the outer surface of the first coating and a second coating 5B applied over the first coating 5~ and its association reinforcing material 4B. The first and second coatings are applied so as to entrap the reinforcing materials between the core and first coating, and first and second coatings, respec-tively. The thermoplastic material of the first coating isdirectly and intimately bonded to the thermoplastic material of the core and the thermoplastic material of the second coating is direetly and intimately bonded to -the thermoplastic of the outer surface of the first coating.
The outer surface of this second coating may be smooth or non-smooth, although any tube produced in the aforementioned manner greatly reduces the interface bond stress sincc tne ~lc:;-ing shear load on the interface between the su~strate and the subsequent layers is spread over a large percentacJe o~ the resultant wall thickness of the whole tubing thereby rcducing the necessity for high artificial bond strength ~f cour~e, further layers of reinforciny material and thermoplas,ic mate-rial may be provided as required for even greater strenyth.
A further embodiment of the present invention is la_ tubing of ribbon-like form as shown in Fig. 8. Such tubin~ is substantially flat with the volume of the inside of the core be-ing substantially zero and contains subs-tantially no air within the inner part of the tubing when not in use. The tubing is cap-able of assuming a tubular form by introduction of internal fluid pressure. Such flattened tubing may be used as hosepipe, being sel~ draining, by virture of the elastic memory of the material for the ribbon-like form. This tubing is more easily formed into a roll and occupies less space for storage than con-ventional round tubing.
The ridges and valleys provide an additional function in this flat embodiment in that they act as hinge-like parts, allowing the hose to readily assume a traditional shape under internal pressure. When the pressure is removed, the hose re-turns to a substantially completely flat profile, ~ue to -the elastic memory of the tubing urging evacuation of the fluid with-in the tubin~.
The present invention generally enables a recluction of up to 30% of the material usecl to form the second tube in com-parison ~ith prior art composite tubinq and still is capable o^
achieving the same resistance to bursting as the conventional tubing. For example, fully flexible polyvinyl chloride tubing according to the present invention can be produced havin~ an overall thickness of no more than about 3 mm and an inside dia-meter of up to about 19 mm, with a capa~ility of working pres-sures as high as ~0 BAR at 20 C.
The excellent fle~.ibilit~y of the tu~in~ of th~ ?res~n_invention is high due to the need for less material or a gi-~-n strength.
The apparatus for manufacturing flexible reinforced tubing of the present comprises a core supply for suppl~ing a flexible tubular core, a reinforcing material suppl~ device for supplying at least one reinforcing material to the outer sllrface of the core and an extruder arranged to extrude a tubular coat-ing of thermoplastic material onto the outer surface of the core in the reinforcing material, the extruder being adapted to en-able a positive air pressure differential to be applied between the exterior and the interior of the coating around the core dur-ing extrusion of the coating.
The method o~ manufacturing flexible reinforced tubing of the present invention includes providing a flexible tubular core of thermaplastic material, supplying reinforcing material to the surfac~ of the core and extruding, by means of an extruder, a thermoplas~ic coating on the outer surface of the tubular core while creating a positive air pressure differential between the exterior and interior of the coating in the extruder during extrusion to urge the coating into intrinsic contact with the core and the reinforcing material. This positive air pres-sure differential during extrusion causes a ~ond to form directly bet~een the core and the coating.
Prefera~ly, the exterior of the coatin~ is at atmos-pheric pre5sure, and a vacu~lm is applied ta the interior of the coating as it is extruded. The coating is suitably extruded as a tube uni~ormly spaced ~rom the surface o~ the core, the vacuum drawinq the coatlng down onto the core while the coating is still in a plastic state.
_g_ ~7~1~
~ he core supply~ may be a reel, but is preferably an-other plastics extruder, continuousl~ forminy a tubular cDre which is cooled in water before passing through the winding d--vice. The reinforcing material suppiy de~Jice is preferably arranged to apply a plurality of reinforcing threads, half the thread running in the opposite direction to the other half.
The apparatus and method are capable of producing tub-ing having typically one third less material than con~entional tubing of the same general structure, internal diameter and burst pressure. The amount of tubing which has to be discarded through bond failure is substantially reduced and higher produc-tion speeds can be achieved.
The apparatus, shown in Figure 4, incluces a first extruder 11 which is a conventional screw feed extruder receiv-ing -thermoplastic material, such as polyvinyl chloride, in the form of granules. The arrangement of the granule feed hopper and feed screw barrel is conventional and these parts are there-fore not shown in de-tail, only a part of the barrel being shown.
The granules are melted and the molten thermoplastic material is forced through an annular die to extrude a tubular core 2, pre-ferably having an external surface consisting of longitudinal ridges and valleys of generally triangular configuration around the tube~ Dies suitable for extruding tubular core 2 are des-cribed in further detail hereinafter with re~ard to Figure 6.
The core 2 is preferably extruded at a temperature of about 140 to 150 C and at a linear speed of about 2000 ft/hr (170 mm/s) and passes through a cooling bath 13 containing a flow of cool-ing water. The cooling bath 13 cools the core ~ to about 70 C
before it reaches a reinforcing material supply, such as winding device 1~ for the application of reinforcing material. ~71ndin~ device 14 is CO,?s~
prised of two contra-rotating drums 14A and 14B, each OL ~Jnic--.
contain a plurality of reels 15 of reinforcing material. Th~
reinforcing material may be comprised of, for example, a te~.tile material, such as yarn or thread, or a metallic ~aterial, such as wire. The reels are arranged to feed the reinforcing mate-rial to the core under a very light tension and spaced apart so as to produce a braided effect, the yarns crossiny but leaving generally diamond-shape spaces therebetween.
The core with the reinforcin~ material thereon passes from winding device 14 into a second eY~truder 16 of similar general configuration to the first extruder 11. The coating material is a thermoplastic material, preferably a material which is similar to or compatible with that used for the core.
Most preferably both the core and the coating material care pol~
vinyl chloride. The coating material is supplied to an annular die which is described hereinafter in more detail with reference to Fig. 5. A vacuum pump 17 is connected to the extruder 16 by means of a vacuum pipe 18. The coated core passes through a second cooling bath 19 whose lenyth, coolant flow rate and tem-perature are selected to reduce the tempera~ure oE the coatinc3 from the extrusion temperature, which may be from about 1~0 ~o 150 C, to a suitable temperature to permit manual handlir.g of the tube, for example, forming into rolls such as on a reei 10.
Referring to Fig. 5, the extruder comprises an elon-gated screw 20 which drives the molten thermoplc~stic coatîng material into the extruding head 21. Elead 21 comprises a ~wo part extruding tool 22, havin~ an outer part 22~ containin~ a frusto-conical bore ?2B therethrougtl an~i a ~enerally rus~o-conical inner part 72C whose conical sur~ce contains all an{31e ~ ~ ~ 7 ~ 1t~
smaller than that contained by the surface of the ;~Gre~ 22~ ,einner part 22C has a cylindrical bore 22D therethrougn, 'h-e di--meter of whieh is larger than -the external diameter of .ne co e 2 with the reinforcing material wound onto the surface thereo so that the prevailing gas pressure at the rear face 22E o. the inner part 22C is substantially the same as that of the opposite end of the bore 22D.
The rear faee 22E is attached to one end of a tubular vaeuum ehamber 23 whieh is in turn attached to an adjusting ring 24 whieh is externally serew-threaded and screws into a corres-pond.ingly-threaded soeket 25 in the body of extruding head 21.
Rotation of -the adjusting ring 24 thus moves the inner part 22C
of the extruding tool relative to outer part 22A whieh in turn alters the thiekness of the eoating extruded.
A vaeuum eonnector piece 26 extends a~ially from adjusting ring 24 and has a bore 27 therethrough whieh eommuni-cates with the interior of vaeuum 23 and with vaeuum tube 28 whieh is eonneeted by flexible hose 8 to vaeuum pump 7 (s~e Fi~.
4). An inlet tube 29, having a tube guide, typically of PTFE, in sealing bushing 30 in the end thereof, e~tends axially from eonneetor pieee 26 and the interior of the tube communieates with the interior of COnneCtGr piece 26.
Bushing 30 makes sealing contact with the core as it enters the inlet tube 29 and passes through the vacuum chamber to the extruding tool, thus maintaining the vacuum.
The eoating material delivered to the extrudin~ head 21 by screw 20 passes into an annular space 31 surrounclincJ the vaeuum chamber 23 and Erom there into the space bet~.~een the inner and outer parts 22C and 22A of the e:;trllclincJ tool. The matèrial is extruded at a rat~ such that it fl.ows out of the ~12-annular gap at the outlet of the e~truding tool 22 a~ s~ s~an-i-ally the same speed as out of the annular ga? ~t the outle' 'J--the extruding tool 22 and substanti~ the same sDeed as _ha-at which the core 2 passes through the extruder, t~picall,~
170 mm/sec. The vacuum in the vacuum chamber -is com~unicated to the inside of the coating at the point of e.~trusion. Tn~ coat-ing is extruded substantially parallel to thc core and the vacuum, of the order of about 20 to 40 inch ~.Jater gauge, draws the coating into intimate contact with the core and with the reinforciny material wound onto the core. The coating thickness, after being drawn onto the core, is less than the thickness of the core, and the texture of the reinforcing material may be felt and may also be seen after coating.
In a first alternative embodiment, the coated tubing passes from the second extruder 16 through cooled nip rollers 32 as shown in Fig. 7 before entering cooling bath 19. `.~ip rolle-s 32 flatten the tubing into a ribbon-like form ~hich may be re-turned to a tubular form by internal fluid pressure. Such flat-tened tubing 33 may be used as hosepipe, being self-clraining, ~y virtue of the elastic memory of the material for the ribbon-like form, more ea~ily Eormed into a roll, and occup~ing less space for storage than conventional round tubing.
In a second alternative embodiment, the coated tuDing from the second extruder 6 passes through a cooling bath wnich brings the temperature down to about 70 C then to a second wind-ing device identical to the first windin~ device ~ whcre a second set of reinforcing materi,ll is applied, and from thcre to a third extruder, of a generally identical construction to thc second extruder 16, where a final outcr coating is applicd, again of a thin thermoplastic material, such as ~oly~inyl chloride. Tubing produced in this manner i~ suitable for J---ry high pressure applications, ~ith operating presa~1res, or example, for a 10 mm internal di~meter tube, in e~cess of ~0 ~A~
at 20 C.
The apparatus for and the method of ~anufacturing o' reinforced flexible tubing of thermoplastic material provides efficient low cost production because production ma~ be carried out in a continuous manner. Such continuous production permits a thin outer coating to be applied over the braid and core and in multilayer tubing prevents problems such as "cold flow" when the tubing is assembled with connectors. Further, tubing pro-duced according to the present invention can be produced at lower COât due to tremendous saving in material weic3ht. Work in progress is non-existent as tubing may be continuously pro~uce~
and scran levels are exeeedinyly low.
In a preferred embodiment of the invention, appro~i-mately 80~ of the thermoplastic m~terial is in the inner corr-and a maximum of about 20~ of the thermoplastic is in ~he outer coating. This allows the outer coating to assume the confic3ura-tion of the ribbed inner core giving the tubing an abrasiQnresistant cover since the contact point at any abrasion arecl is reduced.
In ~ preferred embodiment of th~ invention, tubular core 2 may be extruded utilizing a die o the type shc~wn in Figure 6 to produce the tubular core 2 having an external sur-ace consistiny of lonyitudinal ridqes and valleys of generally triangular confiyuration extending longitudinally on ~he tube.
Reinforced flexible tubiny o~ thermopl~stic material has been successfully produced utilizing dies 3~ "la~in~ t;ne con~icjura-tions shown in Table 1, in first extruder of an appara~l,similar to that shown in Fig. 4. The inside diamPtrr of -.~se core thus produced is also shown in Table 1.
Table I
Die Dimensions Die Core Right Angle Bore W1dth of Ridge Ridge Peak Inside A(degrees) Diameter Valley Base Height Anyle Diameter , B(in.) C~1n.) D(in.) E(degrees) (in.) _ 1 84 0.480 0.012 0.035 la 0.937 2 84 0.550 0.009 0.035 15 0.937 3 ~4 0.725 0.035 0.023 1~ 0.875 4 84 U.915 0.013 0.028 ~ 0.81~
Bushing 30 makes sealing contact with the core as it enters the inlet tube 29 and passes through the vacuum chamber to the extruding tool, thus maintaining the vacuum.
The eoating material delivered to the extrudin~ head 21 by screw 20 passes into an annular space 31 surrounclincJ the vaeuum chamber 23 and Erom there into the space bet~.~een the inner and outer parts 22C and 22A of the e:;trllclincJ tool. The matèrial is extruded at a rat~ such that it fl.ows out of the ~12-annular gap at the outlet of the e~truding tool 22 a~ s~ s~an-i-ally the same speed as out of the annular ga? ~t the outle' 'J--the extruding tool 22 and substanti~ the same sDeed as _ha-at which the core 2 passes through the extruder, t~picall,~
170 mm/sec. The vacuum in the vacuum chamber -is com~unicated to the inside of the coating at the point of e.~trusion. Tn~ coat-ing is extruded substantially parallel to thc core and the vacuum, of the order of about 20 to 40 inch ~.Jater gauge, draws the coating into intimate contact with the core and with the reinforciny material wound onto the core. The coating thickness, after being drawn onto the core, is less than the thickness of the core, and the texture of the reinforcing material may be felt and may also be seen after coating.
In a first alternative embodiment, the coated tubing passes from the second extruder 16 through cooled nip rollers 32 as shown in Fig. 7 before entering cooling bath 19. `.~ip rolle-s 32 flatten the tubing into a ribbon-like form ~hich may be re-turned to a tubular form by internal fluid pressure. Such flat-tened tubing 33 may be used as hosepipe, being self-clraining, ~y virtue of the elastic memory of the material for the ribbon-like form, more ea~ily Eormed into a roll, and occup~ing less space for storage than conventional round tubing.
In a second alternative embodiment, the coated tuDing from the second extruder 6 passes through a cooling bath wnich brings the temperature down to about 70 C then to a second wind-ing device identical to the first windin~ device ~ whcre a second set of reinforcing materi,ll is applied, and from thcre to a third extruder, of a generally identical construction to thc second extruder 16, where a final outcr coating is applicd, again of a thin thermoplastic material, such as ~oly~inyl chloride. Tubing produced in this manner i~ suitable for J---ry high pressure applications, ~ith operating presa~1res, or example, for a 10 mm internal di~meter tube, in e~cess of ~0 ~A~
at 20 C.
The apparatus for and the method of ~anufacturing o' reinforced flexible tubing of thermoplastic material provides efficient low cost production because production ma~ be carried out in a continuous manner. Such continuous production permits a thin outer coating to be applied over the braid and core and in multilayer tubing prevents problems such as "cold flow" when the tubing is assembled with connectors. Further, tubing pro-duced according to the present invention can be produced at lower COât due to tremendous saving in material weic3ht. Work in progress is non-existent as tubing may be continuously pro~uce~
and scran levels are exeeedinyly low.
In a preferred embodiment of the invention, appro~i-mately 80~ of the thermoplastic m~terial is in the inner corr-and a maximum of about 20~ of the thermoplastic is in ~he outer coating. This allows the outer coating to assume the confic3ura-tion of the ribbed inner core giving the tubing an abrasiQnresistant cover since the contact point at any abrasion arecl is reduced.
In ~ preferred embodiment of th~ invention, tubular core 2 may be extruded utilizing a die o the type shc~wn in Figure 6 to produce the tubular core 2 having an external sur-ace consistiny of lonyitudinal ridqes and valleys of generally triangular confiyuration extending longitudinally on ~he tube.
Reinforced flexible tubiny o~ thermopl~stic material has been successfully produced utilizing dies 3~ "la~in~ t;ne con~icjura-tions shown in Table 1, in first extruder of an appara~l,similar to that shown in Fig. 4. The inside diamPtrr of -.~se core thus produced is also shown in Table 1.
Table I
Die Dimensions Die Core Right Angle Bore W1dth of Ridge Ridge Peak Inside A(degrees) Diameter Valley Base Height Anyle Diameter , B(in.) C~1n.) D(in.) E(degrees) (in.) _ 1 84 0.480 0.012 0.035 la 0.937 2 84 0.550 0.009 0.035 15 0.937 3 ~4 0.725 0.035 0.023 1~ 0.875 4 84 U.915 0.013 0.028 ~ 0.81~
5 84 0.980 0.014 0.035 9 0.750
6 84 1.512 0.003 0.~35 5 0.593 The present invention will be further illustrated by the following examples which are intended merely to illustrate the present invention and are not intended to limit the scope o the invention which is defined in the claims.
EXAMPLE
A 1at hose was produced in accordance with the method described hereinbefore with reference to Figures 4 and 7, as the first alternative embodiment. The internal diameter of the tube before passaye through the nip rollers was 12 mm. The nominal overall wall thickness was 2 mm, with the height of the ridqes, relative to the valleys, being 0.58 mm. The outer coating thic~-ness was approximately 1 mm relative to the valleys. The over-all weight of the hose was 93 g/m. Samples of the tube were tested for burst pressure by applying gradually increasing hydro-static pressure to a sealed sectlon o~ the tube. The minumum ~73~3 burst pressure out of a number of samples "as found to D" 4~
p.s.i.g. (3.l ~INm ) and burst pressures .~ere generally in ex-cess of 500 p.s.i.g. (3.45 MNm ).
COMPARATIVE EX~MPLE 1 Round hoses were prepared in accordance with the main method hereinbefore described with reference to Figures 4 and ~.
Hoses of exactly the same nominal dimensions were produced by a similar process, but without the application of ~Jacuum. Each hose was tested for burst pressure as in the Example herein-before.
The results were as follows:
BURST PRESSURE
lat 20C) (psig) Nominal Internal COAT:[NG COATING
Diameter ~mm) WITHOUT WITH
VACUUM VACUU~
6 ll90 1300 12 790 ~50 19 575 6~5 -Hoses were produced using the methods as in Comparative Example l, but, in the case of the hoses coated with-out application of ~acuum, the coating thickness was such that the burst pressures of the hoses coated with the without vacuum were generally the same. The resulting weights of th~ hoses 'or a unit length were compared, and Table 2 gives the result.
Nominal Internal ~EIG~T (g~m) Diameter ~mm) COATING COATING
WITHOUT WITH
VACUUM VACUU~`I
6 ~0.8 5 165 '~
l~ 22~ 126 19 331~ ~5 COMPARATIVE EX~PLE 3 1 A hose manufactured in accordance with the me~ od .-:ere-inbefore described with reference to Figures 4 and 5 was tested to compare the strength of bonding between the coating and ~he core with a conventional gas hose having a similar general con-struction, but a smooth core tube and coating applied without vacuum. The hoses were both high pressure gas hoses of 10 mm internal diameter.
300 mm lengths of each type of hose were used as test specimens. A hypodermic needle was inserted at one end of the hose at the junction between the coating and the core. The hose was plugged and secured with hose clips, the needle extendin~
beyond the clip at one end. Each sample was immersed in ~ater during the test, and air was supplied under pressure to the hypodermic needle.
Samples in accordance with the invention were pres-surized for 20 hours at 50 p.s.i.g. (3~3 kNm 2), and for one hour at 60 p.s.i.g. (414 kNm 2) at 80 p.s.i.g. (552 kNm 2), an~l no leak was detected at the end of this time.
A sample of the conventional hose showed air leak~s from both ends, from ~e-tween the layers, after only a few minutes at a pressure of 10 p.s.i.g. (69 kNm ).
EXAMPLE
A 1at hose was produced in accordance with the method described hereinbefore with reference to Figures 4 and 7, as the first alternative embodiment. The internal diameter of the tube before passaye through the nip rollers was 12 mm. The nominal overall wall thickness was 2 mm, with the height of the ridqes, relative to the valleys, being 0.58 mm. The outer coating thic~-ness was approximately 1 mm relative to the valleys. The over-all weight of the hose was 93 g/m. Samples of the tube were tested for burst pressure by applying gradually increasing hydro-static pressure to a sealed sectlon o~ the tube. The minumum ~73~3 burst pressure out of a number of samples "as found to D" 4~
p.s.i.g. (3.l ~INm ) and burst pressures .~ere generally in ex-cess of 500 p.s.i.g. (3.45 MNm ).
COMPARATIVE EX~MPLE 1 Round hoses were prepared in accordance with the main method hereinbefore described with reference to Figures 4 and ~.
Hoses of exactly the same nominal dimensions were produced by a similar process, but without the application of ~Jacuum. Each hose was tested for burst pressure as in the Example herein-before.
The results were as follows:
BURST PRESSURE
lat 20C) (psig) Nominal Internal COAT:[NG COATING
Diameter ~mm) WITHOUT WITH
VACUUM VACUU~
6 ll90 1300 12 790 ~50 19 575 6~5 -Hoses were produced using the methods as in Comparative Example l, but, in the case of the hoses coated with-out application of ~acuum, the coating thickness was such that the burst pressures of the hoses coated with the without vacuum were generally the same. The resulting weights of th~ hoses 'or a unit length were compared, and Table 2 gives the result.
Nominal Internal ~EIG~T (g~m) Diameter ~mm) COATING COATING
WITHOUT WITH
VACUUM VACUU~`I
6 ~0.8 5 165 '~
l~ 22~ 126 19 331~ ~5 COMPARATIVE EX~PLE 3 1 A hose manufactured in accordance with the me~ od .-:ere-inbefore described with reference to Figures 4 and 5 was tested to compare the strength of bonding between the coating and ~he core with a conventional gas hose having a similar general con-struction, but a smooth core tube and coating applied without vacuum. The hoses were both high pressure gas hoses of 10 mm internal diameter.
300 mm lengths of each type of hose were used as test specimens. A hypodermic needle was inserted at one end of the hose at the junction between the coating and the core. The hose was plugged and secured with hose clips, the needle extendin~
beyond the clip at one end. Each sample was immersed in ~ater during the test, and air was supplied under pressure to the hypodermic needle.
Samples in accordance with the invention were pres-surized for 20 hours at 50 p.s.i.g. (3~3 kNm 2), and for one hour at 60 p.s.i.g. (414 kNm 2) at 80 p.s.i.g. (552 kNm 2), an~l no leak was detected at the end of this time.
A sample of the conventional hose showed air leak~s from both ends, from ~e-tween the layers, after only a few minutes at a pressure of 10 p.s.i.g. (69 kNm ).
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for manufacturing reinforced flexible tubing of thermoplastic material comprising:
a) a core supply for supplying a flexible tubular core;
b) a reinforcing material supply device for supplying reinforcing material to the outer surface of said core; and c) an extruder arranged to extrude a coating of thermoplastic material onto the outer surface of said core and said reinforcing material, said extruder being adapted to enable a positive air pressure differential to be applied between the exterior and interior of said coating around said core during extrusion of said coating.
a) a core supply for supplying a flexible tubular core;
b) a reinforcing material supply device for supplying reinforcing material to the outer surface of said core; and c) an extruder arranged to extrude a coating of thermoplastic material onto the outer surface of said core and said reinforcing material, said extruder being adapted to enable a positive air pressure differential to be applied between the exterior and interior of said coating around said core during extrusion of said coating.
2. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, wherein said core supply is an extruder.
3. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, wherein said core supply is an extruder adapted to extrude a tubular core having an external surface consisting of longitudinal ridges and valleys of generally triangular configuration around the tube.
4. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, wherein said reinforcing material supply device is a winding device.
5. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 4, wherein said winding device comprises two contra-rotating drums, each of which contain a plurality of reels of reinforcing material.
6. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 5, wherein said reels are arranged to feed reinforcing material to said tubular core under very light tension and spaced apart to produce a braid effect.
7. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 2, further comprising a cooling bath for cooling said extruded core before application of said reinforcing material.
8. An apparatus for manufacturing reinforced Flexible tubing as claimed in claim 1, wherein a vacuum means creates said positive air pressure differential.
9. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, wherein said extruder comprises an elongated screw and an extruding head having an outer part containing a frusto-conical bore therethrough and an inner part having a frusto-conical outer surface, the conical angle of which is less than that of said outer part, and a cylindrical bore therethrough, and wherein said rear face of said extruding head is attached to vacuum means.
10. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, further comprising nip rollers for flattening said coated tubing into a substantially flat ribbon-like form.
11. An apparatus for manufacturing reinforced flexible tubing as claimed in claim 1, further comprising:
d) a second reinforcing material supply device for supplying reinforcing material to the outer surface of said coated tubing; and e) a second extruder arranged to extrude a second coating of thermoplastic material onto the outer surface of said coated tubing and said reinforcing material, said second extruder being adapted to enable a positive air pressure differential to be applied between the exterior and interior of said second coating around said coated tubing during extrusion.
d) a second reinforcing material supply device for supplying reinforcing material to the outer surface of said coated tubing; and e) a second extruder arranged to extrude a second coating of thermoplastic material onto the outer surface of said coated tubing and said reinforcing material, said second extruder being adapted to enable a positive air pressure differential to be applied between the exterior and interior of said second coating around said coated tubing during extrusion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000515733A CA1227313A (en) | 1983-11-04 | 1986-08-11 | Flexible tubing and method of manufacturing same |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000440447A CA1209493A (en) | 1983-11-04 | 1983-11-04 | Flexible tubing and apparatus for and method of manufacturing same |
| CA000515733A CA1227313A (en) | 1983-11-04 | 1986-08-11 | Flexible tubing and method of manufacturing same |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000440447A Division CA1209493A (en) | 1983-11-04 | 1983-11-04 | Flexible tubing and apparatus for and method of manufacturing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1227313A true CA1227313A (en) | 1987-09-29 |
Family
ID=4126446
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000440447A Expired CA1209493A (en) | 1983-11-04 | 1983-11-04 | Flexible tubing and apparatus for and method of manufacturing same |
| CA000515733A Expired CA1227313A (en) | 1983-11-04 | 1986-08-11 | Flexible tubing and method of manufacturing same |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000440447A Expired CA1209493A (en) | 1983-11-04 | 1983-11-04 | Flexible tubing and apparatus for and method of manufacturing same |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA1209493A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10744696B2 (en) | 2017-02-17 | 2020-08-18 | Fermatex Vascular Technologies, Llc | Reinforced coreless tube extrusion systems and methods |
-
1983
- 1983-11-04 CA CA000440447A patent/CA1209493A/en not_active Expired
-
1986
- 1986-08-11 CA CA000515733A patent/CA1227313A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CA1209493A (en) | 1986-08-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2810424A (en) | Method and apparatus for making reinforced plastic tubing | |
| US4788088A (en) | Apparatus and method of making a reinforced plastic laminate structure and products resulting therefrom | |
| CA1079161A (en) | Method of making push-pull cable conduit and product | |
| US4259991A (en) | High pressure hose construction and method of and apparatus for making the same | |
| DE69204712T2 (en) | Process for the continuous production of an elastic tubular structure with an integrated single-layer layer in micro thickness and elastic tubular structures which are produced by this method. | |
| US4302266A (en) | Method for making high pressure hose | |
| EP0380543A1 (en) | Method of making a catheter or tube. | |
| WO1995010247A1 (en) | Reinforced vascular graft and method of making same | |
| CA1315510C (en) | Fibre reinforced polymer compositions and process and apparatus for production thereof | |
| JPH06169868A (en) | Thread reinforced hose and its manufacture | |
| CN202082504U (en) | Fibre reinforced thermoplastic plastic pipe | |
| US5212341A (en) | Co-extruded shock tube | |
| CA1227313A (en) | Flexible tubing and method of manufacturing same | |
| WO2007121906A1 (en) | Hose line provided with reinforcement element and method and apparatus for its production | |
| HUE025245T2 (en) | Method of manufacturing a pipe from thermoplastic material | |
| EP0036674B1 (en) | Method of making plastics tubing | |
| GB2142270A (en) | Extruded flexible reinforced tubing | |
| JPH03149485A (en) | Multiple-unit tube | |
| JPH044132A (en) | Manufacture of fiber-reinforced thermoplastic resin pipe | |
| JP2001050435A (en) | Compound flexible pipe and manufacture thereof | |
| JP3214892B2 (en) | Method for producing hollow cross-section shaped body | |
| JPH086847B2 (en) | Composite pipe and manufacturing method thereof | |
| RU2660082C2 (en) | Method, manufacturing line and working station for continuously manufacturing reinforced flexible hose, and hose manufactured thereby | |
| CA2075738C (en) | Co-extruded shock tube | |
| WO2021180842A1 (en) | Thermoplastic hose, and a device and a method for producing such a hose |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |