NO761444L - - Google Patents

Description

REINFORCED PLASTIC ROD AND PROCEDURE FOR MANUFACTURE THE SAME.

Reinforced plastic rudders using a known construction method are mostly designed as so-called sandwich rudders which have a layer of plastic-bonded filler granules between glass fiber reinforced plastic layers, e.g. sandy. Through suitable orientation of the glass fiber reinforcement in the affected areas

layers, the axial strength and/or roundness of such a rudder can be varied. Thereby, however, it turns out that rudders that have great strength both for radial loads and for axial loads can only be manufactured with relative difficulty and require a particularly large amount of glass, and thus become expensive. This applies particularly to rudders with medium diameters (e.g. between 40 and 150 cm), which are to be laid in soil for which high density requirements are made with considerable difficulty. Above this, the invention has the task of providing an artificial rudder of the aforementioned type which can withstand heavy loads both in the axial direction and in the radial direction. For this purpose, the synthetic rudder according to the invention is characterized in that it contains a coaxial to the rudder axis

helically wound reinforcement inlay. This post can

consist of fibre-reinforced plastic or metal. It can be arranged, e.g. in an intermediate layer lying between two fiberglass-reinforced plastic layers, or e.g. in a radial outside the usual

the reinforcement layers lying down, e.g. just another thin tire-

layer or insulation layer bearing layer.

The method for producing such a rudder, which nevertheless forms the subject of the invention, is characterized by the fact that, at the earliest during production, this is provided with at least a fiber-reinforced plastic layer with a helically shaped reinforced reinforcement., Thus, for example, in a rotating rudder mold before or after the construction of a fiber-reinforced plastic layer, the the helix-shaped reinforcement insert (spiral) is introduced, after which material necessary for embedding the insert or for further layer removal is introduced into the hollow form. However, the helix-shaped reinforced reinforcement insert could also only follow the e.g. by winding in a hollow shape or by winding on a core, the manufacture of a rudder body is pushed on or wrapped around this, after which the rudder by applying further material, e.g. when winding or placing shell parts is fully lined.

It may be appropriate to introduce the "inlay spiral" only after the production of an outer fiber-reinforced layer, although it is also possible to proceed in such a way that the fiber reinforcement of an outer layer is introduced at the same time as the "inlay spiral" and only then''1'1 • the necessary for the layer formation materia let, i.e. plastic and filler (e.g. sand), are brought in.

If such a rudder is used for passing liquid with a relatively high temperature, e.g. hot water, difficulties often arise due to different thermal expansion of "steel spiral", and glass fiber reinforced plastic. When the "steel spiral" is located in the central area of the rudder wall, it can prevent the free expansion of the inner wall layer to such an extent that between this inner layer and the outer layer, of the freely expanding rudder wall, undesirably large stresses arise, especially when pressure and/or or buoyancy stresses, which occur when rudders are placed in the ground, lead to layer separation or breakage. Nor can the arrangement of the "steel spiral" in the outermost layer of the rudder solve this problem, as e.g. in the case of ground laying of such a rudder, unavoidable bending or shear stresses between the "steel spiral" and the glass fiber-reinforced plastic can lead to breakage of the rudder.

The present invention, on the other hand, also allows these difficulties to be avoided as it provides a rudder or a method for its production, whereby stresses leading to breakage cannot occur. For this purpose, according to the invention, the plastic floor of the aforementioned type is characterized in that the "spiral" which at least encloses a glass fiber reinforced inner plastic layer is enclosed by a protective layer which is separated from an outer plastic layer by a heat-insulating felt material.

The mentioned rudder can be particularly advantageously produced in such a way that the "spiral" is wound on an inner tube of glass-fibre reinforced plastic and covered with a protective layer and subsequently inserted coaxially and at a radial distance into a plastic outer tube, whereupon the annulus between the inner tube and outer tube is filled with a hardening plastic foam .

Thanks to the insulation layer placed between the spiral and the cutter, stresses that lead to breakage can no longer occur and the thus obtained rudder is also excellently suited for laying in the ground for the transport of liquids with a high temperature.

The attached drawing shows schematically and in axial section exemplary embodiments of rudders according to the invention; through this drawing, the manufacturing process according to the invention is also illustrated in the following by examples, as the drawing shows: fig. 1 a first example with wound reinforced plastic insert,

fig. 2 another example with coiled metal insert,

fig. 3 a third example with two coaxially arranged wound metal inserts,

fig. 4 a fourth example with wound reinforced plastic insert,

•fig. 5 in axial section a further example of a rudder according to the invention immediately after its manufacture, and

fig. 6 in axial section, the connection point of two rudders according to the invention.

That in fig. The rudder shown in 1 has a glass fiber-reinforced outer plastic layer 1, an inner filler layer 2 made of plastic-bound granules, in which is inserted a helical insert 3 formed of glass fiber-reinforced plastic, an inner glass fiber-reinforced plastic layer 4 and an inner plastic cover layer 5. Such a rudder for example 1 can be produced as follows: First, using isophthalic acid ester resin and glass roving as reinforcement, the insert 3 is produced; the glass content is approx. 60, the resin content approx. 40% by weight. The winding cross-section showing insert 3 in the shape of a coil spring is square. For a rudder to be manufactured with an outer cross-section of 1000 mm and an inner cross-section of 980 mm, e.g. the outer insert cross-section is 988 mm, the radial thickness of the spring wire 4 mm, the axial width of the spring wire 5 mm and the axial distance of two spring turns 3 mm. Then glass fiber pieces of e.g. 50 mm long and orthophthalic acid resin as plastic for the outer layer that forms has a thickness of 1 mm. The glass content of this layer is expediently at approx. 50% by weight. Sand and orthophthalic acid resin are then introduced into the rotating mold to a layer thickness of approx. 1 mm. Now the formed layers are gelled at 80°. Next, the pre-produced inserts' 3 are introduced into the stationary mold and then further sand and orthophthalic acid are introduced into the rotating mold to the sand/resin layer 2 in which the insert is embedded 3 mm when the total thickness of approx. 7 mm. Next, the rotating mold is fed glass fiber pieces and orthophthalic acid resin to the inner reinforced layer 4 which forms when a thickness of approx. 2 mm. After the gelation of this layer, a flexible cover layer 5 with approx. 1 mm wall thickness on which the rudder is hardened at approx. 120°.

The fixed rudder thus formed was exposed to pressure from the inside with the help of water, which resulted in a breaking pressure of 40 kg/cm<2> for rudders not axially loaded. Leakage of the rudder first appeared at 0.6% axial expansion. A comparison rudder which

in

had the same layer structure, but no spring insert 3, on the other hand gave a compressive strength from the inside of only 25 kg/cm 2 and was already leaking at a load of 10 kg per cm 2 which led to an axial expansion of 0.25%.

An otherwise analogous rudder, in the manufacture of which instead of orthophthalic acid resin isophthalic acid resin and for the insert instead of isophthalic acid resin epopy resin was used, showed at 23°C a breaking pressure of 50 kg/cm and at 100° such a

40 kg/cm2.

That in fig. The rudder shown in 2 has an outer glass fiber reinforced plastic layer 11, a filling layer 12 formed of plastic bound granules in which a helically wound steel wire insert 13 is embedded, an inner glass fiber reinforced plastic layer 14 and an inner synthetic fabric cover layer 15. Such a rudder can e.g. produced as follows: A rotating hollow mold of approx. 500 mm internal cross-section is supplied with 50 mm long fiberglass pieces (60 ends Rowing) together with isophthalic acid polyester resin. Thereby, with the help of an air stream and by suitable choice of the mold rotational speed, it is achieved that the glass fiber pieces are embedded oriented in the plastic layer 11 on all sides and not just in the direction of the extent. After achieving a layer thickness of approx. 1 mm, sand and isophthalic acid resin are added to the rudder mold and this likewise first to a layer thickness of approx. 1 mm. It is now gelled with heat and then the mold is braked, after which the steel spring insert 13 is inserted into the mold. In this example, the outer cross-section of this insert is 496 mm, while the wire cross-section is 2 mm and the axial distance between two windings 10 mm. The rotating mold is then further fed with sand and isophthalic acid resin until the total layer thickness of layer 12 is approx. 5 mm. Then, to form the reinforced layer 14, pieces of glass fiber and isophthalic acid resin are added and then to a layer thickness of 2 mm, the end is made by adding vinyl polyester resin to form the cover layer 15.

This rudder showed an axial strength of 240 kg/cm in tests

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a fracture expansion of 0.8%. The stiffness of the rudder (—qS-) amounted to 4000 N/m<2>. The tightness test with water gave a leak at 23°C and an internal pressure of 16 kg/cm 2 . When using 100 ocl of warm water, the rudder leaked at 20 kg/cm2.

the speed of the steel wire in the insert 13 130 kg/cm 2.

In an otherwise identically designed variant of the rudder described above, a wire spring was used whose axial winding distance was 3 instead of 10 mm. This rudder was tested with earth gas and it remained tight up to an internal pressure of 50 kg/cm.

By that in fig. The rudder shown in 3 is in a filler layer 22 which lies between two fiberglass-reinforced layers 21 and 24, two radially spaced steel wire springs 23a, 23b embedded; the rudder is further equipped with an inner cover layer 25. When manufacturing this rudder, it can e.g. proceed as follows: 1 a rotating hollow mold with an internal cross-section of e.g. 800 mm

glass fiber pieces and polyester resin are inserted to form the layer 21; the layer thickness is approx. 1 mm. Then gels and

. the hollow mold is slowed down. Now the first steel wire cutter is being introduced

23a with an outer cross section of 798 mm; the wire cross-section is 2 mm and the axial winding distance 13 mm. Then introduced

in the rotary mold sand and polyester resin to a layer thickness of approx. 14 mm after which it is gelled. The second steel spring insert 23b with an outer cross-section of 770 mm is now inserted into the braked hollow form; the wire cross-section is 2 mm and the winding distance 13 mm. Next, this rotating mold is fed again with some sand and resin until the f-jaar 23b is completely stuffed into the layer 22, after which the mold is fed with pieces of glass fiber and polyester resin to form the layer 24, whose layer thickness is approx. 2 mm. The subsequent installed cover layer has a layer thickness of approx. 1 mm.

Such a rudder was tested with oil at a pressure of 20 kg/cm 2; it remained dense underneath. It also withstood an external pressure of 8 kg/cm 2 caused by water. The rudder otherwise showed excellent electrostatic properties which could be further improved through conductive connection of both steel wire inserts 23a, 23b, whereby the individual rudders in one wire could be connected by means of sleeves so that the steel wire inserts of the successive rudders are conductively connected to each other through the sleeves.

in

That in fig. The rudder shown in 4 has an outer mainly axially oriented glass fiber (Roving), reinforced plastic layer 31,

a helically wound insert 33 inserted in a plastic-bonded granule layer 32, made of glass-fibre-reinforced plastic, an inner glass-fibre-reinforced plastic layer 34 and an inner cover layer 35. This rudder can e.g. produced as follows: In the rudder form with an internal cross-section of e.g. 1000 mm glass roving is inserted with a mainly axial orientation and at the same time the prefabricated insert 32 is inserted. The radial thickness of the insert is approx. 4."mm. The rotary mold is now fed with polyester resin until the glass roving is completely impregnated by a layer about 2 mm thick and the insert 33 is completely plugged. Then a formation of the reinforced layer 34 is fed up to a layer thickness of 2 mm in addition to the resin 50 mm long glass fiber pieces, after which the inner cover layer with a thickness of approx. 1 mm is brought in.

The testing of this rudder gave an axial strength of 900 kg/cm<2>

and a fracture expansion of 1.5% in the axial direction. By a

internal pressure induced with water on . 10 kg/cm 2 the rudder remained tight up to an axial expansion of 1.2%.

Based on the foregoing, it appears that with the measures described, especially thanks to the helically wound insert, rudders can be produced which, both with regard to internal pressure and also with regard to axial load, have previously unachieved high strengths and impeccable tightness.

It should be understood that analogously to this described method, rudders with a different layer order, number of layers and type of layers combined with similar or other helically wound reinforcement inserts can also be produced. Moreover, it is also possible to produce the described rudders not through centrifugation in a hollow form (i.e. from the outside in), but also e.g. using a "Dornes" from the inside out, partly by spraying, partly by winding the individual layer materials. A combination of both methods is also conceivable. Likewise, it is possible instead of \ 2 insert swings of the same material (reinforced plastic or

steel wire) to place two posts of different material.

That in fig. The combination rudder shown in 5 consists of an inner tube (41) made of glass-fibre-reinforced plastic, which is enclosed by a steel winding 42 stuffed in plastic and covered with a plastic protective layer, further by a relatively thick filling layer 43 of the insulating material that surrounds the inner tube and by a cap tube 44

of fiberglass-reinforced plastic that encloses the filling layer. For the production of. this combination rudder is, for example, proceeded as follows: In the sling stop process, the inner rudder 41 is produced using heat-resistant plastics, e.g. with a cross section of 500 mm and a wall thickness of 7 mm. However, the internal error could also be produced after the winding process. After hardening and shaping, the steel spiral 42 is wound on the inner core, e.g. with a wire cross-section of 2 mm and a winding distance of approx. 5 mm. Plastic spatula mass is then spatted between the wire turns and gelled. A thin plastic laminate with high bfuddut width and good temperature component is therefore applied to the thus prepared inner error; for the gelation of this plastic layer, a thin glass fiber mat is fixed on it, so that the outside of this now fully treated inner tube is formed of clean, non-impregnated glass fibers. After the same loop stop process, a synthetic fur is further produced, e.g. with a cross section of 600 mm a water thickness of 3 mm; thereby ensuring that the inner rafts of this rudder have artificial glass fibres;

of course glass fibers can also be at hand underneath which are completely stuffed in the plastic. After hardening and shaping, the two rudders as fig. 5 shows arranged coaxially with each other, after which the annulus remaining between them, as mentioned, is limited by plastic-free glass fibres, foamed out with a hardening plastic; the plastic foam connects the inner space and the fairing rudder to a combination rudder with high stiffness.

It has been shown that the described combination rudder, when laid in soil with cover heights of 5 to 6 metres, has a deformation of less than 1%. Since the steel spiral in the central area of the rudder wall is therefore close to the neutral axis, the bending stresses are small there and therefore also the shear stresses that occur between the steel spiral and plastic. When hot liquids are passed through, pressure stresses can occur in the inner hole as the steel spiral limits the expansion of the inner plastic layer; between the laminate that surrounds the vane and the inner plastic layer, certain radial stresses can thereby arise; however, as laminated has very thin walls and the plastic has increased flexibility when heated, these radial stresses are small and cannot lead to breakage.

The aforementioned laminate prevents water from coming to the coil from the outside, which could lead to correction.

As the relevant rudders can only be produced in predetermined lengths, they must be connected to each other for the production of cables. An example of such a connection which protects both the spiral and the rinsing foam against water penetrating from the inside or outside is shown in fig. 6. Also in the combination tube sections shown here, the inner tube is denoted by 41, the steel spiral by 42, the insulating layer by 43 and the jacket tube by 44. As can be seen in the drawing, the glass fiber reinforced inner tube 41 protrudes beyond the spiral 42, respectively the tube layers 43 and 44 which enclosed.

At the point of contact for the two rudder sections, the protruding part of the inner furrow 41 on one side and the two cutter rudders 44 on the other side are connected by a sleeve part 45 and 46 respectively; in order to prevent an axial separation of the connected rudder sections, intervening securing lines 47 are placed in the grooves of the cutter rudder 44 and the outer sleeve part 46; axially within these rings 47 are recesses, the outer sleeve part 46 is fitted with arranged sealing rings 48. As the drawing shows, the two sleeve parts 45, 46 are designed symmetrically with respect to the center plane of the contact point and are connected to each other by the insulation material 49 analogously to that of the rudder layer 43. Such a rudder connection also allows the manufacture of axially loaded e.g. hot water conducting rudder lines. It is therefore expedient to orient the glass fiber reinforcement in the inner hole at least

partly in the circumferential direction and that of the cutter in the axial direction. As heat-resistant plastics for the inner tube, epoxy resins, bisphenol polyester resins or vinyl ester resins have been shown to

be appropriate. The spatula mass that is inserted between the windings of the steel spiral should also be heat resistant; in particular, it should have the smallest possible thermal expansion coefficient and have little friction against the steel spiral; for this purpose, the spatula mass is advantageously mixed with a large proportion of a suitable filler such as quartz flour or kaolin.

The spiral protective laminate does not need to be heat resistant; a glass fiber-reinforced plastic laminate is used expediently, whereby a glass fiber mat is advantageously placed as lamination; the plastic must be flexible when exposed to heat and e.g. have more than 3% elongation at break at 90°.

.As described, a steel wire spiral is suitable. especially as a spiral..

In certain cases, a spiral made of glass fiber-reinforced plastic can also be arranged, provided that it is made with a relatively high glass content and with particularly heat-resistant plastic.

Claims (26)

1. Reinforced synthetic rudder with at least one filler layer lying between two fibre-reinforced layers, characterized in that it contains at least one coaxial to the rudder axis helically wound reinforcement insert. 2. Reinforced synthetic fiber according to claim 1, characterized in that the spiral insert (3 or 33) consists of glass fiber reinforced synthetic material. 3. Reinforced synthetic fiber according to claim 1, characterized in that the spiral insert (13 and 23a, 23b respectively) consists of steel wire. 4. Reinforced synthetic fiber in accordance with claim 1, character list r t in that the spiral-shaped insert is placed in a layer between two fibre-reinforced horizontal filling layers. 5. Reinforced synthetic fiber according to claim 1, characterized in that two coaxial and radially spaced helical inserts (23a, 23b) have been placed. 6. Reinforced synthetic fiber according to claim 5, characterized in that the two inserts (23a, 23b) consist of steel wire and are embedded in the same filling layer (22). 7. Reinforced synthetic fiber according to one of the preceding claims 1-6, characterized in that the layers are made up of orthophthalic acid resin. 8. Reinforced synthetic fiber according to one of the preceding claims 1-6, characterized in that the layers are made of isophthalic acid resin. 9. Reinforced synthetic fiber according to one of the preceding claims 1-6, characterized in that the layers are made up of polyester resin. 10. Reinforced synthetic fiber according to claim 2, characterized in that the spiral insert (13 and 23a, 23b respectively) consists of isophthalic acid polyester resin and glass roving. 11. Reinforced synthetic fiber according to claim 2, characterized in that the spiral insert (13 and 23a, 23b respectively) consists of epoxy resin and glass roving. 12. Reinforced synthetic fiber according to one of claims 1-3, characterized in that at least one spiral which encloses a glass-fibre reinforced inner synthetic layer is surrounded by a protective layer which is separated from an outer synthetic layer by a heat-insulating filler. 13. Reinforced synthetic fiber according to claim 12, characterized by the fact that the spiral is embedded in a spatula mass which contains a friction-reducing filler and an outer fiberglass layer reinforced plastic laminate as a protective layer. 14. Reinforced plastic floor according to claim 13, characterized in that the laminate consists of a heat-flexible plastic whose elongation at break at 90° is over 3%. 15. Reinforced synthetic furrow according to claim 14, characterized in that the insulating layer is a synthetic material foam. 16. Reinforced plastic rudder according to claim 15, characterized in that two coaxially adjacent rudder sections are connected by a coupling sleeve symmetrical with respect to the plane of contact, which has a counter-axial separation under force application with the outer reinforced plastic layer of the rudder section tightly connected outer sleeve part and an inner sleeve part tightly connected to the inner reinforced plastic layer of the wheel section, whose sleeve parts are connected to each other by insulating material by e.g. plastic foam. 17. Reinforced synthetic fiber according to claim 14, characterized in that the glass fiber reinforcement in the inner synthetic layer is mainly oriented in the circumferential direction and that in the outer synthetic layer mainly in the axial direction. 18. Reinforced synthetic fiber according to claim 12, characterized in that, instead of the spiral, a further mainly circumferentially oriented glass fiber reinforcement of the inner synthetic layer is placed. 19. Method for the production of the plastic floor according to claim 1, characterized in that at the earliest with the production of at least 1 fibre-reinforced plastic layer, this is equipped with a helically wound reinforcement. ; 20. Method according to claim 19, characterized in that in a rotating hollow mold at the latest after the build-up of an outer fiber-reinforced layer, the helically wound reinforcement insert is inserted into a hollow mold, whereupon the materials required for the layer formation are inserted into the rotating mold. 21. Method according to claim 20, characterized in that a fiberglass-reinforced plastic layer is formed in the rotating mold by inserting glass and plastic, after which part of the filling layer is produced by inserting sand and plastic, with a stationary mold the insert spiral is inserted and with a rotating mold the rest of the filler layer and then by inserting glass and plastic, the second glass fiber reinforced layer is produced. 22. Method according to claim 20, characterized in that, together with the glass fiber reinforcement for the production of a reinforced plastic layer, the insert spiral is inserted into the stationary hollow mold, after which the plastic is introduced in a rotating mold to form the outer reinforced layer and the filler layer, on which to form the inner reinforced layer, glass and plastic is brought into the mold. 23. Method according to claim 19, characterized in that after manufacturing a glass fiber-reinforced inner tube with a wound spiral and after covering the latter with a plastic laminate, this inner tube is positioned coaxially and with a radial distance in a glass fiber-reinforced plastic tube with a larger cross-section, after which the annular space between the two the rudders are filled with hardening filler foam. 24. Method according to claim 23, characterized in that the outer surface of the spiral of the inner tube and the inner surface of the cap tube are both provided with detached glass fibers which, by subsequent foaming of the tubes placed in each other, improve their connection with the plastic foam. 25. Method according to claim 23, or 24, characterized in that at least the cutting rudder is produced by winding. 26. Method according to claim 23 or 24, characterized in that at least the inner error is produced by winding.