DE102016219556A1 - Vacuum device for a pultrusion process, method for operating a vacuum device in a pultrusion process and use of the vacuum device - Google Patents

Abstract

The invention relates to a vacuum device (5, 5 ', 5 ") for a pultrusion process for the continuous production of blanks from a fiber-plastic composite material (23) and to a method for operating a vacuum device (5, 5', 5"). in a pultrusion process and the use of a vacuum device (5, 5 ', 5 ") according to the invention. The vacuum device according to the invention has at least one vacuum chamber (52, 52 ', 52' ') and at least one connecting element (54, 54', 54 '') which is suitable for connection to a vacuum pump, wherein - the at least one vacuum chamber (52, 52 ', 52' ') is designed such that by means of a vacuum pump, a negative relative pressure in a strand of unimpregnated fibers (21) is generated, wherein the strand of unimpregnated fibers (21) continuously translationally through the at least one vacuum chamber (52, 52 ', 52' '), and wherein - at least one sealing element (53, 56, 56' ', 581) is arranged at the inlet of the strand of unimpregnated fibers (21) into the at least one vacuum chamber (52, 52', 52 '') '') is arranged, the sealing surface is adapted to completely comprise the strand of non-impregnated fibers (21) in the region of entry into the at least one vacuum chamber (52, 52 ', 52' '). The vacuum device (5, 5 ', 5 ") according to the invention is advantageously suitable for a high drawing speed in the pultrusion process.

Description

The invention relates to a vacuum device for a pultrusion process for the continuous production of blanks made of a fiber-plastic composite material (FKV) and a method for operating a vacuum device in a pultrusion process and the use of a vacuum device according to the invention.

The pultrusion process, also referred to as pultrusion, allows continuous production of fiber-plastic composite (FRP) profiles, in particular continuous fiber reinforced composite profiles. In the pultrusion process, a strand of (reinforcing) fibers and semi-finished fiber products, in particular endless reinforcing fibers, by means of a take-off device by a device for producing a FRP profile, which is generally a device for embedding the fibers in a plastic matrix, also referred to as impregnation, and a curing and shaping device, pulled. The process speeds of the individual process steps of the pultrusion process determine the drawing speed, ie the speed with which the strand is pulled through the device for carrying out the pultrusion process.

The shaping is usually carried out by means of a heated tool in which the curing of the matrix material of the FRP profile takes place at the same time. Since the curing takes a certain amount of time, the drawing speed that can be used in a heated tool pultrusion process is limited. To increase the drawing speed, on the one hand, the heated tool can be extended while keeping the tool temperature constant, so that the dwell time of the strand impregnated with matrix material in the tool is lengthened. By extending the tool adversely increases the friction that is exposed to the strand, which results in higher, applied by the trigger withdrawal forces and a higher probability of damage of the fibers of the strand. On the other hand, an acceleration of the curing process can be achieved by increasing the mold temperature while keeping the tool length constant. The disadvantage here is that the temperature distribution is not homogeneous, in particular in the case of large strand cross sections, so that localized hardening in the tool often occurs, or premature hardening of the surface of the strand, leading to surface cracking or blistering the surface can lead after exiting the tool. Furthermore, possible local overheating of the matrix material can lead to its chemical decomposition.

From the EP 1347114 A2 a pultrusion process is known in which the method steps of molding and curing are separated from each other to overcome the disadvantages described. For this purpose, a shaping, made of plastic, permanent formwork is used, in which the curing can be done independently of the actual pultrusion process. The lost formwork is easily filled in the pultrusion process with fibers that are impregnated with matrix material, and sealed. No measures are described which avoid incomplete impregnation of the fibers or air inclusions during impregnation, so that it can be assumed that the FRP profiles produced by means of the disclosed process are of reduced quality.

The aim of the impregnation step is to completely cover each element of the semifinished fiber with matrix material. Incompletely wetted elements and air pockets in the matrix degrade the mechanical properties of a FRP profile and are undesirable. For this reason, the impregnation is often carried out by injection of the matrix material under significantly increased relative pressure, wherein the relative pressure represents the pressure difference between the pressure prevailing in the device absolute pressure and the ambient pressure (in general, the air pressure). However, this pressure increase is not sufficient, in particular for matrix materials of higher viscosity, in order to avoid the aforementioned undesired effects. From the prior art, various other approaches are known to improve the quality of impregnation of a strand with matrix material. In the US 5073413 A a pultrusion device is described, which has two chambers, wherein in the first first matrix material is injected into a strand of unimpregnated fibers, and then in the second chamber, the strand of now impregnated fibers is subjected to a degassing process by passing through the chamber, in which a negative relative pressure (negative pressure) prevails, is pulled. A disadvantage of this solution is that the matrix material represents an increased flow resistance for air bubbles which are to escape in the radial direction from the interior of the fiber strand. In particular, in strands with large cross-sections, the residence time in the vacuum chamber must be chosen accordingly long, so that the pulling speed is low by the pultrusion device.

A similar concept for a pultrusion process is in the JP H05318608 A disclosed; Here, an impregnation of the strand by injection of Matrix material from at least two points, between which the already impregnated strand is subjected to a negative pressure, so that during the first impregnation trapped air bubbles escape from the strand. The sealing of the strand area, which is exposed to the negative pressure, with respect to the environment takes place in that the strand area is separated from the environment on both sides by strand areas soaked in matrix material. This method also has the aforementioned drawbacks due to the trapped air flow resistance increased by the matrix material.

The sealing of vacuum systems to which material is continuously supplied, can be done by locks, such as in the DE 20 2004 005216 U1 described when the material is in separate units. For sealing translationally moving passages on vacuum systems is in the DE 10 2013 109882 A1 discloses an arrangement of a plurality of sealing rings, wherein in the sealing gaps is a sealing lubricant, which would lead to contamination of the strand. Both solutions are not suitable for sealing a continuous fiber strand that enters and exits the vacuum system without interruption.

The object of the present invention is therefore to overcome the disadvantages of the prior art and to propose a vacuum device for a pultrusion process by means of which higher drawing speeds can be achieved in the pultrusion process, without the mechanical properties of the fiber-plastic composite blank produced by the pultrusion process be negatively influenced.

This object is achieved by a vacuum device for a pultrusion process with the features of claim 1 and a method for operating a vacuum device in a pultrusion process.

• – die mindestens eine Vakuumkammer so ausgestaltet ist, dass, insbesondere mittels einer Vakuumpumpe, ein negativer Relativdruck in einem Strang aus ungetränkten Fasern erzeugt werden kann, wobei der Strang aus ungetränkten Fasern kontinuierlich translatorisch durch die Vakuumkammer bewegt wird, und wobei
• – zumindest am Eintritt des Strangs aus ungetränkten Fasern in die mindestens eine Vakuumkammer Dichtungselemente angeordnet sind, deren Dichtflächen geeignet sind, den Strang aus ungetränkten Fasern im Bereich des Eintritts in die mindestens eine Vakuumkammer vollständig zu umfassen.

The vacuum device according to the invention for a pultrusion process for the continuous production of blanks made of fiber-plastic composite material has at least one vacuum chamber and at least one connection element which is suitable for connection of a vacuum pump, wherein

• - The at least one vacuum chamber is designed so that, in particular by means of a vacuum pump, a negative relative pressure in a strand of non-impregnated fibers can be produced, wherein the strand of unimpregnated fibers is moved continuously translationally through the vacuum chamber, and wherein
• - At least at the inlet of the strand of unimpregnated fibers in the at least one vacuum chamber sealing elements are arranged, the sealing surfaces are adapted to completely comprise the strand of non-impregnated fibers in the region of entry into the at least one vacuum chamber.

Preferably, at the inlet of the strand of unimpregnated fibers are arranged in the at least one vacuum chamber and at the outlet of the strand of unimpregnated fibers from the at least one vacuum chamber sealing elements whose sealing surfaces are suitable, the strand of unimpregnated fibers in the region of entry into and out of completely enclose the vacuum chamber.

The term "fibers" in the context of the invention also includes all suitable semi-finished products made of fibers. The vacuum device according to the invention can be supplied both single filaments and rovings, in particular continuous fibers, as well as any suitable for pultrusion fiber semi-finished, for example, scrims, knitted fabrics, braids, mats, nonwovens, as well as combinations of different fiber or semi-finished fiber types. Natural or synthetic fibers, for example glass or carbon or aramid fibers, or mixtures of different fiber types may be used.

"Impregnated fibers" in the sense of the invention are fibers or semi-finished fiber products which are not wetted with matrix material. The provision of the non-impregnated fibers and their supply to the vacuum device according to the invention takes place from a storage area, which may comprise, for example, a coil stand and / or a braiding wheel and / or a winding wheel and / or a stand for material strips. After deduction from the storage area, the bundling of the fibers is made into a strand.

The term "strand" refers to an arrangement of bundled fibers which is continuously translationally moved to carry out the pultrusion process. The term "strand" in this sense also includes an arrangement of bundled fibers and a mandrel, as used for producing a hollow profile in the pultrusion process.

The movement of the strand through the at least one vacuum chamber takes place continuously, ie spatially and temporally without interruption, translationally in the pultrusion direction. The movement takes place by means of a take-off device, for example a puller known from the prior art, a belt pull-off device or a drum pull-off device. As "Pultrusionsrichtung" is referred to in the sense of the invention, the direction in which the According to the invention, the vacuum device and the subsequent devices for carrying out a pultrusion process are passed through. In the following, all position information refers, unless otherwise stated, to the pultrusion direction.

The vacuum device according to the invention is designed such that in the at least one vacuum chamber a negative relative pressure acts on the strand of unimpregnated fibers, "negative relative pressure" in the sense of the invention meaning that the absolute pressure prevailing in the vacuum chamber is less than the ambient pressure prevailing in the vacuum chamber Stock range prevails, so generally less than the air pressure. Preferably, in the at least one vacuum chamber of the vacuum device, an absolute pressure is established, which is to be assigned to the rough vacuum region. The generation of the negative relative pressure can be effected by means of one or more vacuum pumps, in particular types of vacuum pumps are used which are suitable for operation in the rough vacuum range, for example piston pumps or rotary vane pumps or scroll pumps or water jet pumps. For this purpose, the vacuum device has at least one connection with access to the at least one vacuum chamber, which is suitable for connecting one or more vacuum pumps.

The invention includes not only a vacuum device in which a strand of unimpregnated fibers is disposed, but also a vacuum device adapted to receive the strand of unimpregnated fibers.

For the purposes of the invention, the region of the vacuum device in which the strand can be arranged is referred to as a "strand channel".

Preferably, the vacuum device according to the invention is designed so that in the at least one vacuum chamber, an absolute pressure value less than or equal to 300 mbar, more preferably an absolute pressure value less than or equal to 150 mbar, most preferably an absolute pressure value less than or equal to 50 mbar is generated.

In the vacuum device according to the invention, air is largely removed from the strand of unimpregnated fibers. The residual air content in the strand of unimpregnated fibers when removed from the vacuum device is a function of the absolute pressure in the at least one vacuum chamber of the vacuum device. In this sense, the strand of unimpregnated fibers at removal from the vacuum device is to be described as "almost vacuum".

The at least one vacuum chamber of the vacuum device according to the invention has at the inlet and at the outlet of the strand of non-impregnated fibers sealing elements whose sealing surfaces are adapted to completely encompass the strand of unimpregnated fibers in the region of the inlet and outlet from the vacuum chamber. For the purposes of the invention, the term "sealing surface" is to be understood as the surface of a sealing element at which a sealing effect is achieved.

The term "sealing element" encompasses all elements by means of which undesired flows, in particular air flows, are limited into the reservoir to be sealed by the sealing element, at least to a level which is not harmful to the process.

In order to achieve an airtight seal of the at least one vacuum chamber of the vacuum device according to the invention, it is necessary that a strand of suitable dimensions is arranged in the strand channel of the vacuum device. If no strand is arranged in the strand channel of the vacuum device, the vacuum chamber of the vacuum device according to the invention is open to the environment via the strand channel.

"Air-tight" in the sense of the invention means that the penetration of ambient air is prevented or at least limited to a process-harmless level. Process tolerable is the level of penetrating ambient air into the strand, which is a function of the leak rate in the vacuum chamber, if it does not lead to a mechanical properties of the cured FRP blank negatively affecting formation of air bubbles and pores in the impregnation of the strand in the pultrusion process , "Airtightness" in the sense of the invention includes the tightness at least against non-aggressive fluids.

At least in the pultrusion direction first sealing element of the vacuum device, which is arranged at the inlet of the strand of unimpregnated fibers in the at least one vacuum chamber, serves to seal the vacuum chamber with respect to the environment of

Vacuum Equipment. On the air side of this sealing element ambient air pressure prevails; on the vacuum side of this sealing element prevails in the vacuum chamber adjusting absolute pressure, which is lower than the ambient air pressure. The pressure difference with which the first sealing element is loaded corresponds to the relative pressure in the at least one vacuum chamber.

In the vacuum device according to the invention, a strand with different geometrical cross-sectional shapes can be arranged, for example, round in solid profile or hollow profile shape, oval, in particular in solid profile shape, or polygonal, especially in C, H, I, L or T-profile shape, the cross section of the strand is constant.

Advantageously, a high pull rate for a pultrusion process by the vacuum device according to the invention can be selected, since no limitation of the process speed by long Abpumpzeiten due to reduced flow rates of air bubbles, as they occur in partially or fully impregnated strands in the strand of non-impregnated fibers.

In a preferred embodiment of the vacuum device according to the invention, this has a strand channel, the surface of which, at least in the areas in which contact between the strand and the surface of the strand channel, is made friction-reducing.

A friction-reducing design can be achieved by coating the surface, for. Example, with PTFE (polytetrafluoroethylene), or by a different treatment of the surface, for example, by generating a hemispherical surface on a microscopic scale done. Advantageously, the fiber damage due to friction in the strand channel and the wear of the surface of the strand channel can be reduced by the friction-reducing design of the surface

In a preferred embodiment of the vacuum device according to the invention an injection device is arranged in the pultrusion direction according to the vacuum device according to the invention, in which the strand of non-impregnated fibers, leaving the vacuum device in a nearly depleted state, is impregnated with matrix material. Vacuum device and injection device are connected to each other airtight to the environment. The connection between the vacuum device and the injection device can take place, for example, via a flange with an O-ring seal made of an elastomer.

The vacuum device and the injection device have a continuous strand channel. The strand channel preferably extends without interruption at least over the entire combined length, that is to say the dimension in the pultrusion direction, of the two devices.

In principle, both duroplastic and thermoplastic plastics can be used as the matrix material. Reactive resin systems or fusible plastics are particularly preferably used as matrix material.

In the vacuum device according to the invention, air is almost completely removed from the strand before matrix material is injected into the strand in the subsequent injection device. The impregnation is advantageously carried out due to the fact that the strand is almost completely empty during the impregnation, with particularly complete wetting of the fibers and without pores.

In a further preferred embodiment of the pultrusion method according to the invention, the vacuum device has at least two hermetically interconnected chambers. These chambers are particularly preferably vacuum chambers, very particularly preferably vacuum chambers in which different absolute pressure values representing negative relative pressure values can be set, for example by connecting vacuum pumps of different types to the ports with access to the respective vacuum chambers. Most preferably, each of the vacuum chambers of a vacuum device can have a connection for different vacuum pumps. However, it is also possible to use a vacuum pump for two or more vacuum chambers at the same time.

Preferably, at least in the last in the pultrusion vacuum chamber of the vacuum device, an absolute pressure value is less than or equal to 300 mbar, more preferably an absolute pressure value less than or equal to 150 mbar, most preferably an absolute pressure less than or equal to 50 mbar.

The term "chambers" also includes those chambers, also referred to as "dead chambers", for which no or at least no continuous connection to a vacuum pump is provided. If a dead chamber, for example, arranged between two vacuum chambers, this acts, as in a labyrinth seal, as an extension of the flow path between the vacuum chambers, so that advantageously a lower absolute pressure can be achieved in the rear in the pultrusion vacuum chamber.

Due to the airtight connection unwanted air flows are suppressed in the chambers and between the chambers or at least limited to a process-harmless level.

The pressure difference with which the first sealing element is loaded in the pultrusion direction corresponds to the relative pressure in the first chamber. The pressure difference between the two sides of the sealing elements, which are arranged between the chambers of the vacuum device, is generally lower.

Advantageously, an embodiment of the vacuum device with a plurality of vacuum chambers makes it possible to form a pressure gradient between the vacuum chambers, wherein a particularly low absolute pressure can be achieved at least in the last vacuum chamber in the pultrusion direction.

In a further preferred embodiment of the vacuum device according to the invention, the vacuum device has at least one ring element arranged stationarily around the strand of fibers which is not saturated, and acts as a sealing element of the vacuum device. Particularly preferably, the vacuum device has a plurality of stationary around the strand of non-impregnated fibers arranged ring elements, which are airtight to each other and connected to the environment.

A stationary ring element has at least one stationary region, that is, not moved along with the strand of unimpregnated fibers, in which there is a complete fit with the strand of unimpregnated fibers. This area is also referred to below as the "contact area", even if the fit can be characterized as a clearance fit. This at least one region of a stationary ring element represents a sealing surface, wherein the "sealing surface" is the surface of a sealing element, at which the sealing effect takes place. The characteristic dimensions of the surface enclosed by the sealing surface of at least one stationary ring element are chosen such that they are smaller than or equal to the corresponding characteristic dimensions of the strand of unimpregnated fibers. In the case of a strand of unimpregnated fibers having a circular cross section, the characteristic dimensions correspond to the diameter of the cross section or the diameter of the area enclosed by the sealing surface of a stationary ring element. In the case of a strand of unimpregnated fibers having a quadrangular cross-section, the characteristic dimensions correspond to the diagonals and the side lengths of the cross-section or the diagonals and side lengths of the area enclosed by the sealing surface of a stationary ring element.

Advantageously, the design of the vacuum device with stationary ring elements no joints, in particular no axial joints, i. Dividing joints parallel to the pultrusion direction, on. As a result, fiber damage can be avoided by pinching, especially in unidirectional fibers, as well as increased friction of the strand at the joints.

If the vacuum device consists of several chambers, the following embodiments a) to c) are particularly preferred for the stationary ring elements of the vacuum device:

Embodiment a): The characteristic dimensions of the surface enclosed by the sealing surface of a stationary ring element become smaller in the pultrusion direction relative to each other, wherein the characteristic dimensions of the surface enclosed by the sealing surface of the last stationary ring element in the pultrusion direction are smaller than the characteristic dimensions of the strand of unconsumed fibers are to achieve a high sealing effect. The strand of unconsumed fibers is slightly compressed in the contact area with the last stationary ring element, the compression being very small against the characteristic dimensions of the strand.

The dimensions of the surfaces enclosed by the sealing surfaces of the stationary ring elements arranged in the pultrusion direction in front of the last stationary ring element are greater than or equal to the characteristic dimensions of the strand of unimpregnated fibers. In this embodiment, the low mechanical friction between the sealing surfaces of the stationary ring elements arranged in front of the last stationary ring element and the strand of unimpregnated fibers is advantageous.

Embodiment b): The characteristic dimensions of the enclosed by the sealing surfaces of all stationary ring elements of the vacuum device surfaces are, at least taking into account production-related fluctuations or dimensional tolerances, equal and correspond to the characteristic dimensions of the strand of non-impregnated fibers. Advantageously, in this embodiment, a high sealing effect is achieved on the sealing surfaces of all stationary ring elements. However, there is considerable mechanical friction between the sealing surfaces of the stationary ring elements and the strand of unimpregnated fibers.

Embodiment c): The characteristic dimensions of the surfaces enclosed by the sealing surfaces of all stationary ring elements of the vacuum device are smaller than the characteristic dimensions of the strand of unimpregnated fibers. It is advantageous in this embodiment, the particularly high sealing effect on the sealing surfaces of all stationary ring seals, so that the achievable in particular in the last chamber of the vacuum device absolute pressure is particularly small. The mechanical friction between the sealing surfaces of the stationary ring seals and the strand of unimpregnated fibers is large in this embodiment.

Very particular preference is the embodiment a).

Preferably, the vacuum device according to the invention is designed as an integral, ie one-piece, component, in particular in the described embodiment with stationary ring elements. Advantageously, the integral design has no joints, which fiber damage caused by increased friction at the joints are avoided.

Likewise, the vacuum device can be designed in the described embodiment with stationary ring elements as a modular component, for example, a module comprises at least one chamber. The modules are airtight at least to the environment, for example, via flanges with elastomer seals and bracing elements connected to each other. The number of modules and thus the chambers can be advantageously adapted, for example, to the process conditions and the desired absolute pressure in the last vacuum chamber. Further advantageously, the modular design has no axial parting lines, i. Dividing joints parallel to the pultrusion direction, on.

In an alternative preferred embodiment of the vacuum device according to the invention, this has rotating roller seal elements. In this embodiment, the sealing elements, which have a sealing surface to strand of non-impregnated fibers, not stationary, but consist in rotatably mounted on one axis rollers, wherein the rollers have a rotationally symmetrical, preferably yarn-like, shape. Two rotating roller seal elements are arranged in each case in the form of a half shell and surround the strand of unimpregnated fibers. The rotating roller seals are rotated by the directional movement of the strand of unimpregnated fibers due to rolling friction.

Sealing surfaces consist in this embodiment, not only between each one rotating roller seal member and the strand of non-impregnated fibers, but also between each two rotating roller seal elements which roll with opposite directions of rotation against each other, and between each a rotating roller seal member and stationarily arranged in an airtight housing of the vacuum device sealing elements , which are adapted to seal a rotating roller seal member against the airtight housing of the vacuum device.

In order to increase the sealing effect, at least the sealing surfaces of the rotating roller seal elements can be at least partially covered with sealing means fixedly arranged on the rotating roller seal elements, for example with elastomers. To reduce the existing in particular with the stationary sealing elements of the housing of the vacuum device friction on the sealing surfaces at least the sealing surfaces of the rotating roller seal elements may be at least partially occupied with firmly arranged on the rotating roller seal elements sealing means which have a friction-reducing effect, for example with vacuum greases.

Advantageously, there is substantially no static friction between the strand of unimpregnated fibers moved by the vacuum device and the sealing surfaces of the rotating roller seal elements sealing the strand of unimpregnated fibers, but rolling friction, so that the probability of undesired fiber shifts and / or fiber damage due to adherence of the moving Strand is small at the sealing surfaces. Furthermore, the expended for the drive of the strand in the pultrusion process deducting force can be reduced.

In a further alternative preferred embodiment of the vacuum device according to the invention, this has at least two arrangements of rotating roller seal elements, wherein in an arrangement at least two in the pultrusion direction successively arranged rotating roller seal elements are connected to each other via a sealing belt conveyor belt. A conveyor belt-like arrangement may additionally also have a drive and / or a clamping element for the sealing strip.

The rotatable roller seal elements rotatably mounted on an axle are rotationally symmetrical and preferably designed like a yarn roll. Two rotating roller seal elements are arranged in each case in the form of a half shell and surround the strand of unimpregnated fibers. The sealing tape is a flat band with a closed circumference, which is particularly preferably made of an elastomer. The width of the sealing strip, ie the dimension of the sealing strip parallel to the axis of the rotating roller seal elements, corresponds to about half the circumference of the strand of unimpregnated fibers plus twice the length of the region in which the shell-shaped roller sealing elements are at least indirectly in contact with each other via the sealing strip ,

If the conveyor-belt-like arrangement has a drive element, the sealing strip in the conveyor belt-like arrangement in the pultrusion direction is set in motion by means of this. The Sealing tape can for example also be offset by the movement of the strand in the strand channel in the pultrusion direction in motion, so that no separate drive element is necessary. The shell-shaped roller seal elements roll in opposite directions of rotation against each other, wherein on the sealing surface of each of the rotating roller seal elements to the half-shell-shaped, other rotating roller seal the sealing tape is arranged. The sealing surface of the rotating roller seal elements to each other thus exists between the two sealing bands of at least two conveyor belt-like arrangements. Furthermore, the sealing strip is likewise arranged on the sealing surface of the rotating roller seal elements with the strand of unimpregnated fibers.

The area between two rotating roller seal elements arranged one behind the other in the pultrusion direction of a conveyor belt-like arrangement corresponds to a chamber of the vacuum device. The number of chambers of the vacuum device can be increased by increasing the number of rotating roller seal elements in a conveyor belt-like arrangement. In a chamber of the vacuum device, air can escape from the strand of unimpregnated fibers, since the sealing strip in the region between two in the pultrusion direction successively arranged rotating roller seal elements of a conveyor belt-like arrangement is not airtight on the strand of non-impregnated fibers.

Each rotating roller seal element in the conveyor belt-like arrangement also rolls against a counter-roller element, so that there is a sealing surface between the sealing belt arranged on the rotating roller seal element and the counter-roller element. The counter-roller element rolls sealingly against a stationary arranged on the airtight housing of the vacuum device sealing element.

To reduce the particular existing with the stationary sealing elements of the housing of the vacuum device friction on the sealing surfaces at least the stationary arranged in the vacuum device sealing elements associated sealing surfaces of the rotating roller seal elements and the Gegenrollenelemente can be at least partially occupied with firmly on the rotating roller seal elements and the Gegenrollenelementen arranged sealing means which have a friction-reducing effect, for example with vacuum greases.

It is advantageous in the described embodiment, the probability of undesirable fiber shifts due to the adherence of the moving strand to the sealing surfaces and the probability of fiber damage is low. Furthermore, the expended for the drive of the strand in the pultrusion process deducting force can be reduced. By the described embodiment, a particularly high sealing effect can be achieved.

A further preferred embodiment of the vacuum device according to the invention provides that at least the elements of the vacuum device, which have a contact region with the strand, perform a rotational movement about the strand, wherein the strand is rotationally symmetrical about a strand axis.

The rotational movement around the strand offers positive effects for the processability of the strand by means of the vacuum and / or injection device. The achievable mechanical properties of the strand can advantageously be improved by producing the strand under rotary motion.

Each fiber on the strand surface enters the contact region of an element of the vacuum device at a defined point. The region comprising these defined points is referred to as the entry region of the strand into the contact region.

The described embodiment of the vacuum device according to the invention has the effect that a rotational movement is superimposed on the translatory movement of the strand in the entry region into the contact region of the elements of the vacuum device.

Particularly preferably, the entire vacuum device performs the rotational movement about the strand. However, it is also possible to design the vacuum device such that only portions whose elements or only their elements which have a contact region with the strand execute the rotational movement about the strand, the expansion of the fractions of the elements in the pultrusion direction at least the inlet region of the strand included in the contact area.

Particularly advantageous is the described embodiment of the vacuum device according to the invention in an embodiment of the vacuum device with stationary ring elements.

• i. Bereitstellung eines Strangs aus ungetränkten Fasern;
• ii. Kontinuierliche Zuführung des Strangs aus ungetränkten Fasern zu mindestens einer Vakuumkammer der Vakuumeinrichtung, die mindestens einen Anschluss für eine Vakuumpumpe aufweist;
• iii. Erzeugung eines negativen Relativdrucks in der mindestens einen Vakuumkammer der Vakuumeinrichtung mittels eine Vakuumpumpe, wodurch Luft aus dem Strang aus ungetränkten Fasern entweicht;
• iv. Entnahme des nahezu luftleeren Strangs aus ungetränkten Fasern aus der Vakuumeinrichtung und Zuführung des nahezu luftleeren Strangs aus ungetränkten Fasern zu einer Injektionseinrichtung, wobei Vakuumeinrichtung und Injektionseinrichtung luftdicht zumindest gegenüber der Umgebung miteinander verbunden sind.

The invention further relates to a method for operating a vacuum device for a pultrusion process for the continuous production of blanks of fiber-plastic composite material, which comprises at least the following Process steps performed in the order given:

• i. Providing a strand of unimpregnated fibers;
• ii. Continuously feeding the strand of unimpregnated fibers to at least one vacuum chamber of the vacuum device having at least one port for a vacuum pump;
• iii. Generation of a negative relative pressure in the at least one vacuum chamber of the vacuum device by means of a vacuum pump, whereby air escapes from the strand of unimpregnated fibers;
• iv. Removal of the nearly empty strand of unimpregnated fibers from the vacuum device and feeding the nearly airless strand of unimpregnated fibers to an injection device, wherein the vacuum device and injection device are connected to each other airtight at least relative to the environment.

The injection device has at least one injection chamber, in which the injection of matrix material in a flowable state and the impregnation of the strand with the matrix material takes place. After removal from the injection device, the fiber-plastic composite blank (FKV blank) can be supplied to further process steps, which relate inter alia to at least the curing of the matrix material.

The vacuum device, for the operation of which the inventive method is indicated, has the above-described embodiments of the invention.

Advantageously, due to the fact that a strand of unimpregnated fibers is exposed to a negative relative pressure, in the method according to the invention a high pulling speed can be used.

Another object of the invention is the use of the vacuum device according to the invention in a pultrusion plant comprising at least one injection device.

The invention also relates to the use of the vacuum device according to the invention in a pultrusion process for the production of blanks from a fiber-plastic composite material.

• (1) Bereitstellung eines Strangs aus ungetränkten Fasern;
• (2) Zuführung des Strangs aus ungetränkten Fasern zu der Vakuumeinrichtung;
• (3) Erzeugung eines negativen Relativdrucks in der mindestens einen Vakuumkammer der Vakuumeinrichtung, wodurch Luft aus dem Strang aus ungetränkten Fasern entweicht;
• (4) Entnahme des nahezu luftleeren Strangs aus ungetränkten Fasern aus der Vakuumeinrichtung und Zuführung des nahezu luftleeren Strangs aus ungetränkten Fasern zu einer Injektionseinrichtung, die mindestens eine Injektionskammer aufweist, wobei Vakuumeinrichtung und Injektionseinrichtung luftdicht zumindest gegenüber der Umgebung miteinander verbunden sind;
• (5) Injektion von Matrixmaterial in fließfähigem Zustand in die mindestens eine Injektionskammer der Injektionseinrichtung und Imprägnierung des Strangs mit dem Matrixmaterial;
• (6) Entnahme des Rohlings aus der Injektionseinrichtung.

The invention also provides the use of the vacuum device according to the invention in a pultrusion process for the production of blanks from a fiber-plastic composite material, wherein the pultrusion process has at least the following process steps, which are carried out in the order given:

• (1) providing a strand of unimpregnated fibers;
• (2) feeding the strand of unimpregnated fibers to the vacuum device;
• (3) generating a negative relative pressure in the at least one vacuum chamber of the vacuum device whereby air escapes from the strand of unconsumed fibers;
• (4) removing the near-empty strand of unimpregnated fibers from the vacuum device and feeding the near-empty strand of unimpregnated fibers to an injection device having at least one injection chamber, wherein the vacuum device and injection device are airtight to each other at least connected to the environment;
• (5) injecting matrix material in a flowable state into the at least one injection chamber of the injection device and impregnating the strand with the matrix material;
• (6) Removal of the blank from the injection device.

• (7) Zuführung des Rohlings zu einer Ummantelungseinrichtung;
• (8) Erzeugung einer ummantelten Oberfläche des Rohlings in der Ummantelungseinrichtung, wobei die Ummantelung dazu ausgebildet ist, die Luftdichtheit der Oberfläche des Rohlings bei weiteren Verfahrensschritten, denen der Rohling unterzogen werden kann, sicherzustellen;
• (9) Entnahme des eine Ummantelung aufweisenden Rohlings aus der Ummantelungseinrichtung.

The removal of the FRP blank from the injection device is preferably followed by the following method steps in the order indicated:

• (7) feeding the blank to a sheathing device;
• (8) forming a shrouded surface of the blank in the shroud means, the shroud being adapted to ensure the airtightness of the surface of the blank in further process steps to which the blank may be subjected;
• (9) Removal of the shell having a shell from the sheathing device.

After removal from the sheathing device, the blank can be supplied to further process steps, which may relate inter alia to a shaping treatment and the hardening of the matrix material.

Advantageously, the method steps described enable the further processing of the blank having a casing, in particular a non-chip shaping, without it being possible for air to penetrate into the blank due to damage to the surface of the blank.

For the purposes of the invention, "sheath" is to be understood as meaning all intrinsic and / or extrinsic elements by means of which the blank is provided with a surface which remains airtight when the blank is further processed. One possible further treatment is, in particular, a non-chip shaping in which portions of the surface of the blank are, for example, compressed or stretched. As intrinsic elements are Understand elements that consist of matrix material. Intrinsic elements are in this sense in particular partially consolidated or matrix material in the glass state. Extrinsic elements are elements other than the matrix material, such as films or waxes.

After removal from the injection device or after removal from the sheathing device, the blank passes through the take-off device and a cutting device in which the blank is cut to length. The cutting in the cutting device can also take place much later than the preceding method steps.

If the blank is to be formed, this is done after the production of a coated surface and cutting to length or after cutting to length and the production of a coated surface. The curing of the matrix material takes place in spatial and temporal separation from the described method steps.

The vacuum device according to the invention is suitable for use in the above-described pultrusion process for the production of blanks from a fiber-plastic composite material as a solid material, ie in solid profile form

Furthermore, the vacuum device according to the invention is also suitable for use in the above-described pultrusion process for the production of blanks made of a fiber-plastic composite material as a hollow profile. For this purpose, a rigid or a flexible mandrel is preferably arranged in the strand.

For the production of blanks in hollow profile form, a rigid or flexible mandrel made of solid material can be arranged in the strand around which the fibers or semi-finished fiber products are bundled. Likewise, a rigid or flexible tube can be arranged as a mold core in the strand around which the fibers or semifinished fiber products are bundled. A rigid mold core made of solid material can advantageously be removed after curing of the matrix material, wherein no tools are needed for the curing, for example by pressing. A rigid tube as a mold core can be advantageously removed, for example by drilling. A flexible mold core made of solid material or a flexible tube as a mold core is advantageously used when the blank is to be subjected to shaping, and can be removed after shaping, for example by melting. Furthermore, both a rigid and a flexible mandrel made of solid material or a rigid or flexible tube can remain as a mandrel after hardening of the matrix material in the component.

embodiments

In the following, the vacuum device according to the invention and the method according to the invention for operating a vacuum device for a pultrusion process will be explained in more detail by means of embodiments, without being limited to these exemplary embodiments.

Showing:

1 a schematic representation of a pultrusion plant, which has an embodiment of a vacuum device according to the invention and is suitable for carrying out the method according to the invention;

2a an embodiment for the inventive use of a vacuum device according to the invention;

2 B a further embodiment of the inventive use of a vacuum device according to the invention;

3a an embodiment of a vacuum device according to the invention with a plurality of vacuum chambers in a modular design in longitudinal section, wherein the sectional plane corresponds to the median plane of the strand and is parallel to the Pultrusionsrichtung, and wherein the vacuum device comprises stationary ring elements;

3b an embodiment of a modular vacuum device according to the invention with a plurality of vacuum chambers and stationary ring elements as in 3a wherein the vacuum means comprises elements for performing a rotation about the strand axis;

3c an embodiment of an integral vacuum device according to the invention with a plurality of vacuum chambers and stationary ring elements, shown as in 3a wherein the vacuum means comprises elements for performing a rotation about the strand axis;

4a the side view of an alternative embodiment of a vacuum device according to the invention with a plurality of vacuum chambers, wherein the vacuum device comprises rotating rollers as sealing elements;

4b in the 4a marked view of a cross section along the line AA perpendicular to the pultrusion of the in 4a illustrated embodiment of a vacuum device;

5a the side view of another alternative embodiment of a vacuum device according to the invention with a plurality of vacuum chambers, wherein the vacuum device comprises two conveyor belt-like arrangements with connected via a sealing tape rotating rollers;

5b in the 5a marked view of a cross section along the line AA perpendicular to the pultrusion of the in 5a illustrated embodiment of a vacuum device;

6a an embodiment of an injection device in an integral embodiment in longitudinal section, wherein the sectional plane of the center plane of the strand corresponds and is parallel to the Pultrusionsrichtung;

6b an embodiment of an integral injection device as in 6a wherein the injection device comprises elements for performing a rotation about the strand axis;

7 an alternative embodiment of an injection device in a modular design in longitudinal section, wherein the sectional plane of the center plane of the strand corresponds and is parallel to the Pultrusionsrichtung;

8a a plan view of an embodiment of a sheathing device 7 , wherein the FKV blank is wrapped by rolling with a foil.

8b in the 8a marked view of a cross section of the sheath means along the line AA.

In 1 shows the schematic representation of a pultrusion plant 1 , which is suitable for a FKV blank 23 continuously produce. The FKV blank can be a round, oval or polygonal, z. B. T-shaped, have a cross section. The strand 2 who the pultrusion plant 1 passes through, comprises bundled fibers or semi-finished fiber, which in a storage area 3 are arranged. The storage area 3 exemplifies a coil stand 31 with a variety of coils 310 , of which endless fibers or rovings 311 in the pultrusion direction 11 deducted and in a leadership facility 4 be bundled. The storage area 3 also includes an example of a winding wheel 32 , by means of which, for example, rovings 321 at an adjustable angle to the pultrusion direction on the strand 2 can be stored, and a number of sliver spools 33 of which, for example, slivers 331 , Mats or fleeces for reinforcement on the strand 2 be filed.

The strand of unimpregnated fibers 21 becomes in pultrusion direction 11 in a vacuum device according to the invention 5 he withdrew as a nearly empty strand of unimpregnated fibers 22 leaves. To the vacuum device 5 At least one vacuum pump (not shown) is connected to a negative relative pressure in the vacuum device 5 to create. The almost empty strand of unimpregnated fibers 22 is then placed in an injection device 6 fed, in which he is impregnated. vacuum equipment 5 and injection device 6 are about the connecting element 51 For example, a sealed with an elastomeric O-ring flange, airtight to the environment of the pultrusion plant 1 connected together so that when passing from the vacuum device 5 into the injection device 6 no ambient air into the almost empty strand of unimpregnated fibers 22 penetrates. The injection device leaves the strand completely impregnated with matrix material as FKV blank 23 , The injection device 6 and a sheathing device 7 are about the connecting element 60 , which is sealed for example with an elastomeric O-ring, airtight to the environment of the pultrusion plant 1 interconnected so as to ensure that during the transition from the injection device 6 in the sheathing device 7 no ambient air in the FKV blank 23 penetrates. Because the FKV blank 23 is generally completely impregnated, can be a pultrusion plant 1 even without a connecting element 60 between injection device 6 and sheathing device 7 operate. The FKV blank is made after the impregnation of the sheathing device 7 fed, in a sheathed surface of the FKV blank 23 is produced, wherein the coated surface is also formed airtight when it is stretched, compressed or processed in any other shaping. The one coated surface FKV blank 24 then goes through the trigger means by means of the strand 2 through the pultrusion plant 1 is pulled. The embodiment shows a tape removal device 8th , After the band removal device 8th becomes the FKV blank having a covered surface 24 by means of a cutting device 9 , For example, a saw, cut to the appropriate dimensions and can further process steps (not shown) are supplied.

2a shows schematically an embodiment for the inventive use of a vacuum device according to the invention 5 , The arrangement shown comprises the part of a pultrusion unit of the vacuum device 5 to the injection device 6 , wherein the vacuum device 5 by means of the connecting element 51 airtight to the environment with the injection device 6 is connected, and is capable of, a FKV- blank 23 continuously in the form of a solid profile according to the pultrusion process according to the invention.

A strand of unimpregnated fibers 21 gets into the vacuum device 5 guided, wherein upon entry into the vacuum device 5 bubbles 200 in the strand of unimpregnated fibers 21 are included. In the vacuum device 5 the bubbles escape 200 due to the negative relative pressure produced by means of a vacuum pump (not shown) in the vacuum device 5 is generated, leaving a nearly empty strand of unimpregnated fibers 22 the vacuum device 5 leaves and into the injection device 6 is pulled. In the injection device 6 the impregnation of the almost airless strand of unimpregnated fibers takes place 22 with matrix material 230 , The injection device 6 leaves a fully impregnated FKV blank 23 ,

2 B shows an alternative embodiment for the inventive use of a vacuum device according to the invention 5 , Schematically represented is a section of a pultrusion system that is suitable for a FKV blank 23 in the form of a hollow profile according to one embodiment of the pultrusion process according to the invention to produce continuously and provided with a coated surface. The cutout comprises the part of the pultrusion plant of the vacuum device 5 passing through the connecting element 51 airtight to the environment with the injection device 6 is connected, to the sheathing device 7 passing over the connecting element 60 airtight to the environment with the injection device 6 connected, wherein the airtight connection between injection device 6 and sheathing device 7 is optional.

To a FKV blank 23 to produce in hollow profile form, is a mold core 25 , which consist of solid material or may be tubular, in the strand 2 arranged. The mold core 25 is after a possible shaping (not shown) and after curing of the matrix material 230 removed, for example by pressing, drilling or melting, or remains in the component. As in 2 B clarifies, is first a strand of unimpregnated fibers 21 , wherein the fibers around the mandrel 25 are bundled, in the vacuum device 5 guided, wherein upon entry into the vacuum device 5 bubbles 200 in the strand of unimpregnated fibers 21 are included. In the vacuum device 5 the bubbles escape 200 due to the negative relative pressure produced by means of a vacuum pump (not shown) in the vacuum device 5 is generated, leaving a nearly empty strand of unimpregnated fibers 22 with a mold core 25 the vacuum device 5 leaves and into the injection device 6 is pulled. In the injection device 6 the impregnation of the almost airless strand of unimpregnated fibers takes place 22 with matrix material 230 , The injection device 6 leaves a fully impregnated FKV blank 23 , on its surface in the sheathing device 7 an airtight sheath, shown here as a foil 711 , is arranged. The one coated surface FKV blank 24 is supplied to further, not shown here process steps.

3a shows an embodiment of a vacuum device according to the invention 5 with several successively arranged vacuum chambers 52 in cross-section in the pultrusion direction 11 , wherein the vacuum device 5 a cascade of stationary ring elements 53 includes, which is modular. The components of the vacuum device 5 are substantially symmetrical to a longitudinal plane through the central axis of the strand 2 in the pultrusion direction 11 arranged so that mutually symmetrical components of the vacuum device 5 For reasons of clarity, only once are provided with a reference numeral.

As in all embodiments of the vacuum device according to the invention, the strand occurs 2 as a strand of unimpregnated fibers 21 in the vacuum device 5 and leaves them as a nearly empty strand of unimpregnated fibers 22 , Each stationary ring element 53 has an area 531 on, in the contact between its inner surface 532 (for a better overview are in 3a the contact area 531 and the inner surface 532 only on the first stationary ring element 53 referred to) and the strand 2 so that an airtight seal between the vacuum chambers 52 he follows. The contact area 531 of the first stationary ring element 53 also serves as a seal of the strand channel of the vacuum device 5 opposite the environment. The inner surface 532 a stationary ring element 53 is preferably designed to minimize friction, since the contact area 531 the friction with the strand moving in the strand channel 2 is exposed. By friction-minimizing design, for example, a sliding action between strand 2 and inner surface 532 achieved and / or the contact area between strand 2 and inner surface 532 be minimized, causing fiber damage and abrasion of the inner surface 532 be reduced. For friction-minimizing design, for example, by sandblasting or coating processes, the inner surface on a microscopic scale be designed hemispherical (not shown). Furthermore, in each case two stationary ring elements arranged one behind the other are provided 53 by means of an O-ring 533 and a flange or other suitable connection, here by means of schematically illustrated clamping elements 535 , airtight to the environment connected with each other. Between the vacuum device 5 and the subsequently arranged injection device (not shown) is a relation to the environment airtight connection over that with an O-ring 511 sealed connection element 51 which has, for example, a flange. Also the connecting element 51 has a contact area 512 through, through the last vacuum chamber 52 is sealed airtight against the injection device (not shown).

Every vacuum chamber 52 has a separate connection 54 for each a vacuum pump. It is thus possible to connect vacuum pumps of different types and / or different suction powers and different absolute pressure values in the individual chambers 52 be achieved, the absolute pressure in the pultrusion direction 11 decreases. Likewise it is possible that one or more of these are called vacuum chambers 52 shown chambers is executed as a dead chamber, by after a one-time and only in certain intervals repeating pumping out of air in the dead chamber of the connection 54 For example, by means of a blind flange is hermetically sealed.

The dimensions 534 of the strand channel in the contact area 531 perpendicular to the pultrusion direction 11 are at least in the pultrusion direction 11 last two stationary ring elements 53 smaller than the corresponding dimensions 26 , here smaller than the diameter, of the strand 2 selected. The sealing of the last vacuum chamber 52 is thus particularly good, so that a particularly low absolute pressure value in this vacuum chamber 52 can be achieved. The dimensions 534 the preceding stationary ring elements 53 are about the same or slightly larger than the corresponding dimensions 26 of the strand chosen to reduce the friction of the strand on the inner surface 532 to keep a stationary ring element smaller.

The 3b shows a vacuum device according to the invention 5 as a modular cascade of stationary ring elements 53 similar to the one in 3a , where at the in 3b shown embodiment drive elements 500 are arranged to rotate the vacuum device 5 around the strand axis 27 perform. The strand 2 is rotationally symmetric about the strand axis 27 educated. The rotation becomes a possible damming of the fibers on the surface of the strand 2 in the entry area into the respective contact area 531 the stationary ring elements 53 prevented. Access to the vacuum chambers 52 whose limitation 532 rotates, for the Abpumpvorgang by means of a stationary vacuum pump (not shown), there is a rotary feedthroughs 541 attached to a circumferential groove 542 are arranged.

In 3b is between two vacuum chambers 52 a dead chamber 520 arranged, which has no access to a vacuum pump. The dead chamber 520 acts by lengthening the flow path in the sense of a labyrinth seal, so that advantageous in the pultrusion direction 11 rear vacuum chamber 52 a lower absolute pressure can be achieved.

The 3c shows an embodiment of a vacuum device according to the invention 5 as a cascade of stationary ring elements 53 similar to the representations in 3a and 3b , The vacuum device 5 is not modular but integral. The production can be carried out, for example, by boring or erosion of solid material, so that advantageously no, in particular no axial, joints in the strand channel are arranged, which can lead to fiber damage.

Like the embodiment of 3b has the vacuum device shown 5 elements 500 . 541 . 542 on, through which the vacuum device 5 around the strand axis 27 can rotate.

Due to the friction in the entry region into the contact region, the rotational movement is proportionally transferred to the fibers on the surface of the strand. From the translational movement and the rotational movement, a force on the fibers results at the surface of the strand. Due to this resulting force, a slight, constricting the strand-promoting and thus reducing the diameter of the strand, displacement of the fibers takes place on the surface of the strand, whereby the fibers are placed under additional tensile stress.

The entanglement-promoting effect of the resultant force on a fiber at the strand surface is given except in the case where the direction of the resultant force coincides with the fiber direction vector in the respective associated defined point of the entrance region into the contact region. The fiber direction vector corresponds to the unit vector whose direction reflects the orientation of the fibers on the strand surface. The rotation speed is thus preferably to be chosen such that the case described above does not occur, at least in the majority of the defined points; particularly preferably, the rotational speed is to be selected such that the case described above does not occur for more than 80% of the defined points. From the range available for the selection of the rotational speed, which includes all speeds, due to which a resultant force on the fibers occurs on the strand surface, this rotation speed or these rotational speeds are to be excluded.

The reduction of the diameter of the strand due to the resulting force is very small compared to the diameter of the strand. After leaving the contact region, the displacement of the fibers is almost completely canceled by restoring forces due to the tensile stress. The setpoint geometry of the strand thus does not change to an impermissible extent due to the rotational movement.

The embodiment described has the advantage that a damming of fibers on the surface of the strand in the entry region into the elements of the vacuum device, which have a contact region with the strand, is at least significantly reduced.

The 4a and 4b show an alternative embodiment of a vacuum device according to the invention 5 ' with several successively arranged vacuum chambers 52 ' in an airtight housing 55 ' with several connection elements, eg. B. small flanges, for vacuum pumps 54 ' , In 4a is a side view of the vacuum device 5 ' in the pultrusion direction 11 shown, with the side wall of the housing 55 ' is removed, and in 4b the cross section of the vacuum device 5 ' perpendicular to the pultrusion direction 11 or the plan view of a section through the vacuum device 5 ' along the in 4a shown line AA. The components of the vacuum device 5 ' are substantially symmetrical to a longitudinal plane through the central axis of the strand 2 in the pultrusion direction 11 arranged so that mutually symmetrical components of the vacuum device 5 ' For reasons of clarity, only once are provided with a reference numeral.

For airtight sealing of the vacuum chambers 52 ' against each other and the first vacuum chamber 52 ' towards the environment of the vacuum device 5 ' has the vacuum device 5 ' rotatable on each one to the housing 55 ' sealed axis 561 ' stored rolls 56 ' on, which have a yarn-like shape. In again 4b shown top view of the contact area 562 ' The contact area encloses 562 ' a role 56 ' with the strand 2 the relevant surface of the strand 2 a half-shell. The contact area 562 ' forms the sealing surface between roller 56 ' and strand 2 , By rolling friction in the contact area 562 ' due to the uniform motion of the strand 2 in the pultrusion direction 11 rotates each of the roles 56 ' around its axis 561 ' , In the contact area 563 ' between two roles 56 ' Roll these two roles 56 ' because they have an opposite sense of rotation, against each other, the contact area 563 ' the sealing surface between the two rollers 56 ' forms.

At the housing 55 ' the vacuum device 5 ' are stationary sealing elements 57 ' firmly and airtight arranged. A stationary sealing element 57 ' has a contact area 571 ' in each case to a role 56 ' on, with the role 56 ' in the contact area 571 ' against the stationary sealing element 57 ' rolls. The sealing of a roll 56 ' opposite the housing 55 ' takes place in the contact area 564 ' between role 56 ' and housing 55 ' where the surfaces of roll 56 ' and housing 55 ' in the contact area 564 ' are ground and polished and with vacuum-suitable sealants, such as vacuum greases, are occupied.

The sealing of the vacuum device 5 ' to the injection device (not shown) via the connecting element 51 ' that has an O-ring 511 ' for sealing.

The 5a and 5b show a further alternative embodiment of a vacuum device according to the invention 5 '' with a vacuum chamber 52 '' in an airtight housing 55 '' with a connecting element, for. B. a small flange, for a vacuum pump 54 '' , In 5a is a side view of the vacuum device 5 '' in the pultrusion direction 11 shown, with the side wall of the housing 55 '' is removed, and in 5b the cross section of the vacuum device 5 '' perpendicular to the pultrusion direction 11 or the plan view of a section through the vacuum device 5 '' along the in 5a shown line AA. The components of the vacuum device 5 '' are substantially symmetrical to a longitudinal plane through the central axis of the strand 2 in the pultrusion direction 11 arranged so that mutually symmetrical components of the vacuum device 5 '' For reasons of clarity, only once are provided with a reference numeral.

The vacuum device 5 '' has two arrangements 58 '' from two each in the pultrusion direction 11 successively arranged rotating rollers 56 '' on that over a sealing tape 581 '' with a drive roller 582 '' and a tension roller 583 '' conveyor belt connected to each other. By means of the drive roller 582 '' can the sealing tape 581 '' in the conveyor belt-like arrangement 58 '' be actively set in motion, being the one on the strand 2 arranged portion of the sealing strip 581 '' in the pultrusion direction 11 emotional. The vacuum chamber 52 '' is located between the two rotating rollers arranged one behind the other 56 '' the two conveyor belt-like arrangements 58 '' , Around an additional vacuum chamber in front of or behind the existing vacuum chamber 56 '' to arrange, is an additional rotating role per conveyor belt-like arrangement 58 '' in front of or behind one of the two per arrangement 58 '' existing rotating rollers 56 '' to arrange.

The on an axis 561 '' rotatably mounted rotating rollers 56 '' are rotationally symmetric and have a yarn-like shape. Two rotating wheels each 56 '' are arranged half-shell-shaped to each other. In the contact area 562 '' the rotating rollers 56 '' to the strand and in the contact area 563 '' the rotating rollers 56 '' among each other are the sealing tapes 581 '' of the orders 58 '' arranged. A density-forming contact between strand 2 and the rotating rollers 56 '' as well as between two rotating rollers 56 '' therefore exists indirectly over the sealing tape 581 '' ,

In the vacuum chamber 52 '' There is no sealing contact between the sealing bands 581 '' the two conveyor belt-like arrangements 58 '' , so in the vacuum chamber 52 '' Air can escape from the strand.

Every rotating role 56 '' in the conveyor belt-like arrangements 58 '' rolls sealing against one on an axis 591 '' rotatably mounted counter-roller 59 '' off, so in the contact area 565 '' a sealing surface between the on the rotating roller 56 '' arranged sealing tape 581 '' and the counter-roll 59 '' consists.

On the airtight housing 55 '' the vacuum device 5 '' are stationary sealing elements 57 '' firmly and airtight arranged. A stationary sealing element 57 '' has a contact area 571 '' to each a counter role 59 '' on, with the counter-roll 59 '' in the contact area 571 '' against the stationary sealing element 57 '' rolls. The sealing of the rollers 56 '' . 582 '' . 583 '' . 59 '' opposite the housing 55 '' takes place in the contact area 564 '' . 592 '' (The contact area between the drive and tension rollers and the housing is not shown) between the rollers 56 '' . 582 '' . 583 '' . 59 '' and the housing 55 '' where the surfaces of the rollers 56 '' . 582 '' . 583 '' . 59 '' and the housing 55 '' in the contact area 564 '' . 592 '' are ground and polished and with vacuum-suitable sealants, such as vacuum greases, are occupied.

The sealing of the vacuum device 5 '' to the injection device (not shown) via the connecting element 51 '' that has an O-ring 511 '' for sealing.

6a shows an embodiment of an integrally executed injection device 6 in cross-section in the pultrusion direction 11 , The components of the injection device 6 are substantially symmetrical to a longitudinal plane through the central axis of the strand 2 in the pultrusion direction 11 arranged so that mutually symmetrical components of the injection device 6 For reasons of clarity, only once are provided with a reference numeral.

The strand 2 becomes the injection device 6 as a nearly empty strand of unimpregnated fibers 22 fed and leaves the injection device 6 completely impregnated with matrix material as FKV blank 23 , The injection device 6 has several injection chambers arranged one behind the other 61 on, each via an injection channel 611 are connected to a reservoir for matrix material (not shown). The wall 63 the injection device 6 is as a one-piece component, for. B. casting or rotary part, formed without dividing seams. The injection chambers 61 are separated from each other by contact areas 631 the wall 63 with the strand 2 separated. Due to this, matrix material can enter the individual injection chambers under different absolute pressures 61 generally being the absolute pressure in the pultrusion direction 11 from an injection chamber 61 to the pultrusion direction 11 next injection chamber 61 increases. It is expedient that the absolute pressure of the injection into the first injection chamber 61 chosen low enough to prevent penetration of the matrix material into the vacuum device (not shown) due to the pressure difference.

Because of in the contact areas 631 prevailing friction is the strand channel in the contact areas 631 and as well as on the entire inner surface 632 the wall 63 with a preferably uninterruptible wear protection layer (not shown) occupied.

At the injection device 6 are several Temperierungselemente 64 arranged in order to influence the temperature-dependent viscosity of the matrix material in the desired manner. The Temperierungselemente can serve the heating or cooling and z. B. resistance heaters or heating cartridges or coolant channels or electrical cooling elements.

The airtight connection of the injection device 6 with a front of her arranged vacuum device (not shown) takes place for example via a flange with O-ring 511 ,

The injection device 6 is by means of an O-ring 600 and a suitable, for. B. flange, connecting element 60 opposite one in the pultrusion direction 11 subsequent sheath means (not shown) sealed.

The manufacture of an integrally designed injection device 6 can be done for example by eroding or turning out solid material. For cleaning, for example, cleaning baths can be used.

6b shows the integrally executed injection device 6 of the 6a , wherein at the injection device 6 power Transmission 65 arranged to rotate the injection device 6 around the strand axis 27 to carry out. The strand 2 is rotationally symmetric about the strand axis 27 educated. The rotation becomes a possible damming of the fibers on the surface of the strand 2 in the entry area into the respective contact area 631 the inner surface 632 with the strand 2 prevented. The connection of the stationary matrix reservoir (not shown) to the co-rotating injection channels 611 and drip channels 621 attached to drip compartments 62 are arranged is via rotary unions 660 attached to a circumferential groove 661 are arranged realized. The transmission of electrical power to the Temperierungselemente 64 in the form of electric heaters, for example by means of sliding contacts 662 ,

Due to the friction in the entry region into the contact region, the rotational movement is proportionally transferred to the fibers on the surface of the strand. From the translational movement and the rotational movement, a force on the fibers results at the surface of the strand. Due to this resulting force, a slight, constricting the strand-promoting and thus reducing the diameter of the strand, displacement of the fibers takes place on the surface of the strand, whereby the fibers are placed under additional tensile stress.

The entanglement-promoting effect of the resultant force on a fiber at the strand surface is given except in the case where the direction of the resultant force coincides with the fiber direction vector in the respective associated defined point of the entrance region into the contact region. The fiber direction vector corresponds to the unit vector whose direction reflects the orientation of the fibers on the strand surface. The rotation speed is thus preferably to be chosen such that the case described above does not occur, at least in the majority of the defined points; particularly preferably, the rotational speed is to be selected such that the case described above does not occur for more than 80% of the defined points. From the range available for the selection of the rotational speed, which includes all speeds, due to which a resultant force on the fibers occurs on the strand surface, this rotation speed or these rotational speeds are to be excluded.

The reduction of the diameter of the strand due to the resulting force is very small compared to the diameter of the strand. After leaving the contact region, the displacement of the fibers is almost completely canceled by restoring forces due to the tensile stress. The setpoint geometry of the strand thus does not change to an impermissible extent due to the rotational movement.

The embodiment described has the advantage that a damming of fibers on the surface of the strand in the entry region into the elements of the vacuum device, which have a contact region with the strand, is at least significantly reduced.

7 shows an alternative embodiment of a modular injection device 6 ' in cross-section in the pultrusion direction 11 , The components of the injection device 6 ' are substantially symmetrical to a longitudinal plane through the central axis of the strand 2 in the pultrusion direction 11 arranged so that mutually symmetrical components of the injection device 6 ' For reasons of clarity, only once are provided with a reference numeral.

The injection device 6 ' has a modular design of several separate modules 67 ' . 68 ' on. The number of modules 67 ' . 68 ' can be selected depending on the process parameters of the method according to the invention and adapted in a simple manner. Two modules each 67 ' or a module 67 ' and a module 68 ' are by means of an O-ring 670 ' and by clamping the entirety of the modules 67 ' . 68 ' with clamping elements 69 ' towards the environment of the injection device 6 ' sealed. The inner surface 671 ' a module 67 ' is shaped such that a cavity as an injection chamber 61 ' around the strand 2 formed. Every injection chamber 61 ' has injection channels 611 ' which are connected to a reservoir for matrix material (not shown). The inner surface 681 ' a module 68 ' is shaped such that a cavity as a drip chamber 62 ' around the strand 2 formed. Each drip chamber 62 ' has a drip channel 621 ' which is connected to a drainage channel (not shown) for excess matrix material. Before and after the number of injection modules selected in adaptation to the process parameters 67 ' is in each case a drip module 68 ' arranged. It is also possible to insert modules into the assembly which serve as dead chambers. At every injection module 67 ' is a tempering element 64 ' , z. B. in the form of an electric heater, arranged to influence the viscosity properties of the matrix material via a specific temperature setting.

The sealing of the modules 67 ' . 68 ' between each other by sealing elements 672 ' . 682 ' For example, elastomer sealing lips that are due to the directed movement of the strand 2 through the strand channel in the pultrusion direction 11 align and through the in the injection chambers 67 ' prevailing positive relative pressure sealing to the strand 2 be pressed. The sealing elements 672 ' . 682 ' may due to the modular structure of the injection device 6 ' be replaced in an easy way, if by abrasion due to the movement of the strand 2 worn and the sealing effect wears off.

The airtight connection of the injection device 6 ' with a front of her arranged vacuum device (not shown) takes place for example via a flange with O-ring 511 ,

The 8a and 8b show an embodiment of a sheath device 7 , where the 8a a plan view and the 8b in the 8a marked view of a cross section along the line AA represents. The surface of the FKV blank 23 is by rolling in foil 711 that is from an axis parallel to the FKV blank 23 arranged film storage 71 that rotates on an axis 712 stored, sheathed. The film is fed over the entire length of the FKV blank 23 ; the width of the film 711 , so their dimension parallel to the axis 712 , corresponds to at least the length of the FKV blank 23 , The foil 711 is from the foil store 71 subtracted and guided into an area where several rolls 72 are rotatably mounted, inserted.

The FKV blank 23 leaves the pultrusion plant 1' completely impregnated with matrix material and is conveyed by means of a conveyor belt 80 to the cutting device 9 , z. B. a saw, transported and cut to length. The FKV blank 23 is also transported free-hanging after cutting to the roll area, and the film 711 in a partial area of the surface of the FKV blank 23 pushed to the surface. By rotation of the rollers 72 with the in 7b The direction of rotation represented by arrows is the FKV blank 23 set in rotation with the illustrated opposite direction of rotation. The foil store 71 also rotates with this, the rollers 72 opposite sense of rotation, leaving the film 711 further retracted into the rolling area and completely, until reaching a slight overlap, around the surface of the FKV blank 23 is placed. To seal the overlap, the foil can 711 z. B. be executed self-adhesive. The following is the slide 711 through the tool 73 cut and by further rotation of the rollers 72 and the FKV blank 23 wrinkle-free and firm on the surface of the FKV blank 23 created. The sheathed FKV blank is made by means of an ejector 74 removed from the roll area.

LIST OF REFERENCE NUMBERS

1, 1 '

 pultrusion

2

 strand

200

 bubbles

21

 Strand of unimpregnated fibers

22

 Nearly empty strand of unimpregnated fibers

23

 FRP blank

230

 matrix material

24

 FKV blank with sheathing

25

 mold core

26

 Dimension of the strand

27

 string axis

3

 storage area

31

 creel

310

 Kitchen sink

311

 roving

32

 winding wheel

321

 roving

33

 Fiber reel

331

 sliver

4

 guide means

5, 5 ', 5' '

 vacuum equipment

500

 Drive element for rotation

51, 51 ', 51' '

 connecting member

511, 511 ', 511' '

 O-ring

512

 contact area

513

 Dimension of the strand channel in the contact area

52, 52 ', 52' '

 vacuum chamber

520

 Totkammer

53

 Stationary ring element

531

 Contact area between stationary ring element and strand

532

 Inner surface of a stationary ring element

533

 O-ring

534

 Dimension of the strand channel in the contact area

535

 clamping element

54, 54 ', 54' '

 Connection element for vacuum pump

541

 Rotary union

542

 groove

55 ', 55' '

 Housing of the vacuum device

56 ', 56' '

 Rotating roller

561 ', 561' '

 Axis of the rotating roller

562 ', 562''

 Contact area of rotating roller to strand

563 ', 563' '

 Contact area of two rotating rollers

564 ', 564' '

 Contact area of the rotating roller to the housing

565 ''

 Contact area of the rotating roller to a counter-roller

57 ', 57' '

 Stationary sealing element

571 ', 571' '

 Contact area of the stationary sealing element to a roll

58 ''

 Conveyor belt-like arrangement

581 ''

 sealing tape

582 ''

 capstan

583 ''

 idler

59 ''

 counter-roller

591 ''

 Axis of the counter-roll

592 ''

 Contact area of the counter roller to the housing

6, 6 '

 injection device

60

 connecting member

600, 600 '

 O-ring

61, 61 '

 injection chamber

611, 611 '

 injection channel

62, 62 '

 drip chamber

621, 621 '

 Abtropfkanal

63

 wall

631

 Contact area between wall and strand

632

 Inner surface of the wall

64, 64 '

 temperature regulating

65

 Drive element for rotation

660

 Rotary union

661

 sliding contact

662

 groove

67 '

 injection module

670 '

 O-ring

671 '

 Inner surface of the injection module

672 '

 sealing element

68 '

 Abtropfmodul

681 '

 Inner surface of the drip module

682 '

 sealing element

69 '

 clamping element

7

 wrap means

71

 film storage

711

 foil

712

Axis of the foil store

72

 roll

73

 Tool for foil trimming

74

 ejector

8th

 Strip off device

80

 conveyor belt

9

 cutting device

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1347114 A2 [0004]
• US 5073413 A [0005]
• JP 05318608 A [0006]
• DE 202004005216 U1 [0007]
• DE 102013109882 A1 [0007]

Claims (16)

Vacuum device ( 5 . 5 ' . 5 '' ) for a pultrusion process for the continuous production of blanks of fiber-plastic composite material ( 23 ), comprising at least one vacuum chamber ( 52 . 52 ' . 52 '' ) and at least one connecting element ( 54 . 54 ' . 54 '' ), which is suitable for connection of a vacuum pump, wherein - the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) is configured so that by means of a vacuum pump, a negative relative pressure in a strand of non-impregnated fibers ( 21 ), wherein the strand of unimpregnated fibers ( 21 ) continuously translationally through the at least one vacuum chamber ( 52 . 52 ' . 52 '' ), and wherein - at the entrance of the strand of unimpregnated fibers ( 21 ) into the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) at least one sealing element ( 53 . 56 ' . 56 '' . 581 '' ) whose sealing surface is suitable, the strand of non-impregnated fibers ( 21 ) in the region of entry into the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) completely. Vacuum device ( 5 ) according to claim 1, characterized in that at the outlet of the strand of unimpregnated fibers ( 21 ) from the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) at least one sealing element ( 53 . 56 ' . 56 '' . 581 '' ) whose sealing surface is suitable, the strand of non-impregnated fibers ( 21 ) in the region of the exit from the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) completely. Vacuum device ( 5 ) according to claim 1 or 2, characterized in that the strand channel of the vacuum device ( 5 ) has an at least partially friction reducing executed surface. Vacuum device ( 5 . 5 ' . 5 '' ) according to one of claims 1 to 3, characterized in that the vacuum device ( 5 . 5 ' . 5 '' ) airtight at least to the environment with an injection device ( 6 . 6 ' ) for the impregnation of the strand ( 2 ), the vacuum device ( 5 . 5 ' . 5 '' ) in the pultrusion direction ( 11 ) in front of the injection device ( 6 . 6 ' ) is arranged. Vacuum device ( 5 . 5 ' ) according to one of claims 1 to 4, characterized in that the vacuum device ( 5 . 5 ' ) at least two airtight interconnected chambers ( 52 . 520 . 52 ' ) having. Vacuum device ( 5 . 5 ' ) according to one of claims 1 to 5, characterized in that the vacuum device ( 5 . 5 ' ) at least one stationary around the strand of unimpregnated fibers ( 21 ) arranged ring element ( 53 ) or rotating roller seal elements ( 56 ' ) having. Vacuum device ( 5 ) according to one of claims 1 to 6, characterized in that the vacuum device ( 5 ) is designed as an integral component. Vacuum device ( 5 ) according to one of claims 1 to 7, characterized in that the vacuum device ( 5 ) is executed without axial parting line. Vacuum device ( 5 '' ) according to one of claims 1 to 5, characterized in that the vacuum device ( 5 '' ) at least two arrangements ( 58 '' ) of rotating roller seal elements ( 56 '' ), wherein in an arrangement ( 58 '' ) at least two in the pultrusion direction ( 11 ) arranged behind one another rotating roller seal elements ( 56 '' ) via a sealing tape ( 581 '' ) Are connected to each other in a conveyor belt. Vacuum device ( 5 ) according to one of claims 1 to 9, characterized in that the vacuum device ( 5 ) is designed as a modular component, wherein the modules of the injection device ( 5 ) Are connected to each other airtight at least relative to the environment. Vacuum device ( 5 ) according to one of claims 1 to 10, characterized in that the vacuum device ( 5 ) Elements ( 500 ), by means of which at least the elements of the vacuum device ( 5 ), which has a contact area ( 531 ) with the strand ( 2 ), a rotational movement about the strand ( 2 ) To run. Method for operating a vacuum device ( 5 . 5 ' . 5 '' ) for a pultrusion process for the continuous production of blanks of fiber-plastic composite material ( 23 ), comprising at least the following method steps: i. Provision of a strand of unimpregnated fibers ( 21 ); ii. Feeding the strand of unimpregnated fibers ( 21 ) to a vacuum device ( 5 . 5 ' . 5 '' ) containing at least one vacuum chamber ( 52 . 52 ' . 52 '' ) having; iii. Generation of a negative relative pressure in the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) of the vacuum device ( 5 . 5 ' . 5 '' ), whereby air from the strand of unimpregnated fibers ( 21 ) escapes; iv. Removal of the almost empty strand from unimpregnated fibers ( 22 ) from the vacuum device ( 5 . 5 ' . 5 '' ) and supply of the near-empty strand of non-impregnated fibers ( 22 ) to an injection device ( 6 . 6 ' ), whereby vacuum device ( 5 . 5 ' . 5 '' ) and injection device ( 6 . 6 ' ) Are connected to each other airtight at least relative to the environment. Use of a vacuum device ( 5 . 5 ' . 5 '' ) according to one of claims 1 to 10 in one Pultrusion plant ( 1 ), whereby the pultrusion plant ( 1 ) at least one injection device ( 6 . 6 ' ). Use of a vacuum device ( 5 . 5 ' . 5 '' ) according to one of claims 1 to 11 in a pultrusion process for the continuous production of blanks from a fiber-plastic composite material ( 23 ). Use of a vacuum device ( 5 . 5 ' . 5 '' ) according to one of claims 1 to 11 in a pultrusion process for the continuous production of blanks from a fiber-plastic composite material ( 23 ), wherein the pultrusion process comprises at least the following process steps, which are carried out in the order given: (1) provision of a strand of unimpregnated fibers ( 21 ); (2) Feeding the strand of unimpregnated fibers ( 21 ) to the vacuum device ( 5 . 5 ' . 5 '' ); (3) generation of a negative relative pressure in the at least one vacuum chamber ( 52 . 52 ' . 52 '' ) of the vacuum device ( 5 . 5 ' . 5 '' ), whereby air from the strand of unimpregnated fibers ( 21 ) escapes; (4) removal of the near-empty strand from unimpregnated fibers ( 22 ) from the vacuum device ( 5 . 5 ' . 5 '' ) and supply of the near-empty strand of non-impregnated fibers ( 22 ) to an injection device ( 6 . 6 ' ), whereby vacuum device ( 5 . 5 ' . 5 '' ) and injection device ( 6 . 6 ' ) are connected to each other airtight at least relative to the environment; (5) Injection of matrix material ( 230 ) in a flowable state into the at least one injection chamber ( 61 . 61 ' ) of the injection device ( 6 . 6 ' ) and impregnation of the strand ( 2 ) with the matrix material ( 230 ); (6) removal of the blank ( 23 ) from the injection device ( 6 . 6 ' ). Use of a vacuum device ( 5 . 5 ' . 5 '' ) according to claim 1 to 11 in a pultrusion plant or in a pultrusion process for the continuous production of blanks from a fiber-plastic composite material ( 23 ) as a solid material or for the continuous production of blanks from a fiber-plastic composite material ( 23 ) as a hollow profile, wherein for the production of the hollow profile, a rigid or a flexible mandrel ( 25 ) in the strand ( 2 ) is arranged.

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