NO142161B - PROCEDURE FOR CONTINUOUS PREPARATION OF STRENGTHEN HOSE OF ELASTOMERS AND APPARATUS FOR EXECUTION OF THE PROCEDURE - Google Patents

Description

This invention relates to a method for the continuous production of reinforced hoses from elastomers where a hose core is formed from vulcanizable elastomers, pulled off in the axial direction and supported radially over a stretch, within which stretch several reinforcement layers are wound up on the hose core and the elastomer is vulcanized.

Such hoses with a clear width of more than 50 mm and an arbitrarily large length are particularly used as underwater lines at great depths.

The invention also includes a device for carrying out the method and of the kind that includes a mandrel. at the circumference of which rotatable rollers are arranged obliquely.

For use at great sea depths, pipes with a large clearance made of elastomeric plastic and of similar construction to known high-pressure hoses are quite suitable. Such hoses are used -in high-pressure technology for recording high internal pressures, but they have relatively small diameters and short lengths. The technical conditions that must; met in connection with an underwater pipeline for great depths,

cannot be fulfilled by the previously known hose constructions. Firstly, materials that are seawater resistant must of course be chosen. The outside of the hoses must not be attacked by seawater, even after years of use. The outer surface must also be prepared in such a way that fouling and deposition of marine animal remains is limited to a large extent. To cross steep-walled chasms, it is necessary, even with large hose diameters of 300 to 1000 mm, to use lengths of several kilometres. The use of the largest possible individual hose lengths is of great importance to be able to reduce the number of joint zones between the hose ends to the extent that it is technically possible.

The known methods for producing high-pressure hoses of composite material with elastic carrier material can in principle be divided into the spindle method (the mandrel method) and the spindleless method.

According to the spindle method, the individual material components of the hose are placed, e.g. the core part, the reinforcement inlay and the cover layer, individually on a mandrel or spindle which functions as the mold cores. The mandrel length is limited due to the risk of deformation and is usually 20 - 40 m. In the case of discontinuous production, a massive steel mandrel is usually used for the smaller hose diameters, while for larger diameters an aluminum tube is used due to the simpler handling (DT-PS 521 226).

The spindleless methods are so far the only ones that enable the continuous production of hose pieces of any length, as the length limitation due to the deformation is eliminated. The build-up of the hose in the fabric application phase takes place in this case on a somewhat compressed medium, usually air. The fixing of the hose diameters is carried out in this case in connection with the outer diameter, as a lead sheath is applied prior to the heating. after the heating is subtracted continuously. In contrast, to the spindle method, the accuracy of the inner diameters is strongly dependent on the material and machine parameters. Furthermore, for economic reasons, the hitherto known spindle loosening tools are only suitable for use in the production of hoses in larger series and with small hose diameters. (The magazine "Kautschuk und Gummi", February 1963, DK 678.06: 621.643.3).

For the production of high-pressure hoses of the largest and largest diameters, the spindle method has so far only been used. The reason for this is not primarily the requirement for constant inner diameters, but is mainly due to two facts: Firstly, the necessary metal or textile reinforcement for the hose construction must be applied under tension, which when using the spindleless method in connection with hoses with large inner diameters will result in an unacceptable narrowing of the core part. In such cases, it is not possible to increase the support air pressure, as this will also result in a deformation, albeit in a different direction, of the core part. Secondly, the re-encapsulation with lead during the heating would entail economically irresponsible manufacturing costs.

In US patent 2 491 152, a method is described for the continuous production of textile-reinforced hoses of unlimited length. In order to be able to pull off the hose to the same extent as it is produced in the direction of movement without the hose having to be rotated, an annular gap is arranged between the mandrel and the initially unreinforced hose core which is filled with a fluid-shaped storage medium. In the gap, there is thus compressed air as storage medium under three different high pressures. It turns out, however, that in the interior of the annulus which is to be passed by the hose when it slides over the mandrel during construction, shortly after the pressure is applied, a pressure builds up which is the same everywhere and which is equal to the maximum pressure. Thereby, the still unreinforced snake core is inflated like a balloon until it bursts. If, on the other hand, an internal pressure is applied that is lower so that the hose core can withstand the pressure, this leads to a back pressure that is far too weak for the production of high-pressure hoses in the places where the j.forming load is highest. Therefore, this known method of the device used with this device is in principle not usable for the production of hoses with a large clearance.

German specification 1 704 768 describes a device for producing a coiled hose made of plastic. The device has a mandrel to the fixed surface of which is attached several obliquely arranged, driven rollers which wind up the advancing elastomeric band and roll on the cylindrical inner side of the hose. Thus, the hose rotates during production about its longitudinal axis, which, however, must not happen when producing long hose lengths, so that the production of such long hoses cannot be carried out with this device.

German publication 1 778 916 mentions a mandrel for the production of fuel hoses with an inner lining of polyamide and a jacket of neoprene. The mandrel must make it possible for a hose foil made of polyamide to be placed on the mandrel without over-expansion, so that a residual preload is left in the foil. To achieve this, compressed air flows from an annular groove through channels in the direction of pull-up. This compressed air can be shut off after the drawing-up, so that the polyamide foil during forming and vulcanization lies with a certain finished length firmly on the mandrel. It is therefore a device that is not used for the continuous production of hoses.

German publication 1 579 198 describes a method for placing a screw-shaped winding on a hose where a mandrel of limited length clamped between two rotatable liners is used. As the mandrel with the drawn-on hose core rotates, the slide moves along the hose to apply several reinforcing wires as a winding to the hose core. With the help of a guide sleeve, the hose is kept so tight that a uniform laying and position of the threads is achieved. However, this device also does not allow the manufacture of particularly long hoses because the hose is turned during manufacture.

A device for the continuous production of hoses or pipes is known from German patent 735 112. However, like the other known devices, it is only suitable for the production of hoses of limited length, because the hose being produced rotates on its axis, while it is built up by on each other wrapped ribbons.

From the journal "Gummi Asbest Kunststoffe" 1970, issue 8, page 84 8, it is known that the droplets for sealing the inner space in a hollow string can be designed as magnetic bodies.

The purpose of the invention is to provide a method and a device for the continuous production of reinforced

hoses made of elastomers, where the hoses are not rotated during production. This turning must not occur either when the mandrel turns or as a result of torsional forces acting on the hose core during the application of the reinforcement layers.

The method according to the invention is distinguished by the fact that the winding of the reinforcement layers takes place during tightening, that the radial support of the hose core only occurs in the areas of the external force produced by the tightening of the reinforcement layers and that the hose core in these areas is further supported against twisting.

The device for carrying out the method comprises a mandrel with rotatable rollers which are arranged obliquely along the circumference of the mandrel and is distinguished by the fact that the mandrel is arranged to be driven against the direction of rotation by an associated winding device for the reinforcement layers. With the above-mentioned solution, it is achieved that the tightening as a result of wrapping the reinforcement layers is compensated by means of radial supports, while further twisting forces and thus deformation of the hose cross-section are avoided.

The method according to the invention can be carried out in three main variants and using corresponding devices.

The invention will be explained in more detail below by means of

examples with reference to the drawings, where:

Fig. 1 schematically shows a device with a roller mandrel and

an extruder and two wire winders, fig. 2 shows a hydrostatic or aerostatic mandrel, fig. 3 a hollow mandrel with movable bands at the circumference, and fig. 4 another design of the embodiment from fig. 3.

Fig. 5, 6 and 7 show different arrangements of bands in hollow mandrels, fig. 8 shows a device for separate production of the hose core and fig. 9 shows a device with an endless band which, as a result of frictional engagement, is wound on and off a reinforcing layer.

As mentioned, the method according to the invention can be carried out in three main ways: a) With a roller mandrel or roller spindle as shown in fig. 1.

The hose core 2 that leaves the extruder device 1 is maintained in ring-cylindrical shape by a slight overpressure of air in the inner part 3 and is cooled as much as possible before the subsequent treatment process. The hose core is advanced at a constant speed v to the first hose winding machine 4, where it is wrapped with a layer of corded or twisted yarn or thread. In the case of a high-pressure hose, the wire layers must be extremely precise and reproducible, and for this reason a narrowing of the soft and unstable hose core must be avoided under all circumstances.

This is achieved by means of a roller mandrel 5 which rotates in the opposite direction to the cording or twisting machine 4. The roller mandrel 5 is equipped with the largest possible number of slightly convex support rollers 6 whose axis of rotation extends at a variable angle in relation to the center line of the hose. At a given inclined position of the rollers 6 and a given hose withdrawal speed v, the number of revolutions of the roller mandrel 5 is set so that the rollers 6 run along a helical path towards the inner side of the hose core 2.

The roll circle diameter D.^ is also variable in order to be able to run the largest possible hose program with the same roll mandrel. Furthermore, the inner diameter of the hose can be corrected in this way during the manufacturing process.

If a further wreath with support rollers is needed in the second cording or twisting machine 7, this can be turned in the opposite direction to the first by means of a flexible drive shaft 8.

After applying two fiber layers of textile fabric or wire, the hose that is built up is already so pressure-resistant that for further support, an overpressure of several atmospheres in the hose's internal part 9 is sufficient. This pressure medium can advantageously have the necessary temperature for the subsequent heating of the snake.

In order to provide sealing between sections 3 and 9 of the inner part of the hose, a sliding seal 10 is arranged which is rotatably connected to the last roller mandrel 5.

In cases where the torque transmitted by the wire winder 4 or 7 to the hose 2 is not balanced by an equally large

counter torque produced by the roller mandrel 5, a rotation safety device 11 must be provided to prevent a twisting of the hose 2

and an inaccurate thread bearing. This anti-rotation device is preferably arranged as a form-retaining connection between the hose surface and a number of shears that engage in it, or grooved rollers that roll against the surface. The force attack point of the anti-rotation device should be as close as possible to the wire winding point. b) With a hydrostatic or aerostatic mandrel as shown in fig. 2.

The extruded and cooled hose core 2 is in a or

several zones for external force influence protected against compression by a stationary or about its axis rotating support mandrel 13. In order to avoid a contact between the hose core 2 and the mandrel surface, an intermediate gap 15 must be maintained which is filled with a storage medium 14. This storage medium flows under pressure through a supply pipe 15a, capillary pipe 16 in a number of storage pockets 17 and flows from there out through an annular gap 15 and into the hose's inner part 3, from where it returns to the pressure source through return bores 18.

Similar to the method according to a), in all cases where the hose cross-section has insufficient dimensional stability, an additional, external support bearing 19 must be used. This can advantageously be carried out as an aerostatic bearing, as a liquid film between the hose iron 2 and the reinforcement insert 20 will have a detrimental effect on the hose quality. In this way, the hose 2 will be moved slidingly, with minimal friction and constant speed v between the two stationary bearings 13 and 19. The outer bearing 19 conveniently forms part of the coil holder 12 in the hose winding machine 4 and 7

and is provided on the front with guide bores 21 for thread passage. In this way, a bearing enclosure can be arranged on the outside of the hose which is closed in all directions and which extends to the wire application zone.

c) Using a stationary mandrel as shown in fig. 3.

The mandrel 2 3 acts as a calibrator, and where a number of endless,

flexible bands 24 which are carried by the hose 2 in the production retnin-

gene, moves smoothly, with little friction, on the doryter surface. The prerequisite for this is that the coefficient of friction between the inner side of the hose core 2 and the outer side of the bands 24 is significantly greater than the coefficient of friction between the bands 24 and the mandrel 23. If the sliding friction is after all too great in certain production cases, the bands can also be driven by a drive device 25 with the hose withdrawal speed v. Especially with smaller hose inner diameters, it is difficult for reasons of space to place a suitable drive device inside the mandrel, and in such cases the drive device 25 can be placed on the outside, see fig. 4. Such an arrangement is advantageous if the hose core is not extruded, . but is wound by strips 26.

The design of the endless bands 24 is different and adapted to the requirements for a groove-free hose core (figs. 5, 6 and 7). Fig. 5 shows a cross-section along the line A-B through the mandrel according to fig. 3 or 4. The mandrel surface 2 3 is connected by a number of endless bands which are rigid in the longitudinal direction, but sufficiently flexible about their center lines that they can be easily adapted to the curvature of the mandrel. The mutually adjacent side edges 2 7 of the tapes are designed in such a way that they are pressed closely against each other under the influence of an external pressure. The underside of the bands is provided with longitudinal guide steps 29 which are fitted into corresponding recesses 30 in the mandrel surface 23 and thereby prevent a lateral displacement of the bands under the influence of a torque Mfc. The recesses 31 can likewise be arranged on the underside of the bands and run on corresponding guide strips 32 on the doryter surface (fig. 7). In order to reduce the coefficient of friction between the bands 24 and the mandrel 23, bores can be provided for supplying a lubricant.

In the case of non-metallic bands 24, one or more longitudinal stretchers 28 can advantageously be arranged, e.g. of steel wire, within the hose cross-section.

When exerting an external pressure against the hose cross-section to produce a better quality in cases where the hose, after being applied to the textile layer, is wrapped with a hot winding, the inner part 33 of the bands 24 can be filled with gas or liquid, whereby this pressure can be further increased . In such a case, the bands 24 must be made of elastic material which enables a desired thickness increase of the band as a result of the heat expansion of the filler.

Although the edges 27 of the bands 24 are fairly well sealed, an impression of these edges in the form of grooves on the inner side of the finished hose cannot be completely prevented. In any case, to reduce the number of grooves and thus the flow resistance when the hose is in use, the number of bands carried on the mandrel surface must be kept to a minimum, down to one band at the very least (fig. 6 and 7). To facilitate the transfer of the endless band at the ends of the mandrel 23, the band can either be completely (Fig. 6) or partially (Fig. 7) designed with a small thickness, so that the band's cross-section, which is circular along the mandrel surface, can be easily folded at the end of the mandrel and thereby run back into the inner part of the mandrel 34.

In order for the entire mandrel mechanism 2 3 to be fixed in the hose withdrawal direction, the mandrel must be connected to a mandrel holder 22

by means of step 35. As the band 24 in its path through the inner part of the mandrel must run around these steps, the circular cross-section of the band is interrupted in at least one place 36. However, this may be unnecessary if it is possible without mechanical anchoring 22 and 35

to fix the mandrel 2 3 in axial position by means of a strong magnetic field which acts against the mandrel from the inside 36 and/or from the outside 37 (fig. 6). The inside of a hose produced in this way will be completely groove-free and indistinguishable from a conventionally manufactured colander hose.

An axial dowel anchorage without holder 22 is also necessary in cases where the hose core 27 is manufactured in a separate process (fig. 8). The hose core 2, which runs out from a drum 39, is advanced through the wire application zone 40 and the heating zone 41. The finished hose is cooled and then wound on a drum 42.

In order for the work to be carried out "smoothly" also in

such a case of quasi-continuous production, the dbr piece 2 3 which supports the endless bands 2 4 must be fixed to the hose machine in the axial direction without the use of a fixed screw connection. This can be carried out by magnetic means, as shown in fig. 6, or by hydraulic means, fig. 8, whereby a force-resistant connection is obtained. In the case of hydraulic mandrel fixing, the mandrel ends through the steps 35 and a holder 21 are connected to piston surfaces AQ and A. 4 3 which provide a mutual sealing of the inner hose spaces 4 4 and 45.

The gas or liquid pressures in these spaces are connected to each other by means of a regulating device in such a way that the resultant force P-^A^- PqAq of the products of pressure and piston surface at all times balances the frictional force R acting between the bands 24 and the mandrel 23. The axial position of the mandrel 23 can be checked using the known methods for damage-free material testing, e.g. by X-ray, and is corrected through the above-mentioned pressure differential regulation.

As the unreinforced snake core 2 usually cannot resist

a larger, internal pressure in the zone 44 without being deformed to an unacceptable degree, this pressure can be set in accordance with the atmospheric pressure, whereby the front piston surface Ag can be omitted.

In many cases, it can be very advantageous to combine the described methods a), b) and c) with each other. If e.g. the hose cross-section of a hose which has had its first reinforcement insert applied using method c) is already so stable that the subsequent wire layers can be applied during the manufacturing process using method b) or under certain circumstances even just by means of gas or liquid filling in the inner part of the hose, such a combination, provided that the media are separated by means of one or more appropriate seals 10, will be easily implemented.

Despite the precautions described, with each of the methods a) to c), it may occur that the hose cross-section is exposed to an excessive torque, particularly when applying the various reinforcement inserts which are associated with the impact of external forces in a tangential direction to the relevant hose outer diameter. The device shown in fig. 9, has the task to cancel out this torque to the greatest extent possible by an oppositely directed torque of approximately the same magnitude, and to transform the disturbing, external forces into internal forces.

This will mostly be achieved by means of an endless and flexible band 48 which runs close to or together with the fiber or the multi-fibrous or multi-filament fiber connection 47 in the same direction as this and thereby takes up a certain part of the fiber winding tension by frictional action. This effect is made possible partly by the belt 48 being provided with a rough surface, and partly due to the relative speed between 4 7 and 4 8 as a result of their different winding diameters on the hose core 2. As can be seen from section C-D in fig. 9, the endless belt 4 8 which rotates at a speed w, will develop a force S-^ which in the form of a tangential traction affects the hose core 2 and transfers a torque Mfcl to it. When the output force S2 of the belt 48 is brought in accordance with the input force S-^ by propulsion or braking of the diverting roller systems 49-52, the resulting torque M_ will also be equal to M^, whereby the influencing, external forces from the belt result in a constriction of the band part 5 3 which is wound around the hose, as well as a surface force R which develops no torque. This stationary reaction force R is balanced by the stationary mandrel of the embodiment a) to c).

From the above-mentioned examples, it will be clear that in the method according to the invention the hose is manufactured on a stationary spindle or mandrel. The surface of this spindle or mandrel must be moved with the least possible friction in the production direction of the hose that is placed on it. Such a spindle or mandrel constitutes a fixed component of the actual hose manufacturing machine and will be in place at the beginning of the production path possibly right up to the heating zone. Depending on the design, this spindle or mandrel can consist of one or more sub-sections or sub-segments that are designed and arranged so that the spindle segments seen in the direction of production are firmly connected to each other and are only arranged where, due to the application of a new layer of material on the hose , in particular a cord winding or also a heat winding, a pressure is directed from the outside towards the inside of the hose and which must be compensated or equalized in order to counteract deformation of the circular cross-section of the hose.

Claims (2)

1. Method for the continuous production of reinforced hoses from elastomers where a hose core is formed from vulcanizable elastomers, pulled off in the axial direction and supported radially over a stretch, within which stretch several reinforcement layers are wound up on the hose core and the elastomer is vulcanized, characterized in that the winding of the reinforcement layers takes place under tightening, that the radial support of the hose core only occurs in the areas of the external force produced by the tightening of the reinforcement layers and that the hose iron in these areas is further supported against twisting. 2. Device for carrying out the method according to claim 1, comprising a mandrel, at the circumference of which rotatable rollers are arranged at an angle, characterized in that the mandrel (5) is arranged to be driven against the direction of rotation by an assigned winding device for the reinforcement layers.