U.S. patent application number 16/076768 was filed with the patent office on 2021-10-21 for polar cap-reinforced pressure vessel.
The applicant listed for this patent is Enrichment Technology Company Ltd. Zweigniederlassung Deutschland. Invention is credited to Thomas Baumer, Christian Middendorf.
Application Number | 20210324999 16/076768 |
Document ID | / |
Family ID | 1000003692128 |
Filed Date | 2021-10-21 |
United States Patent
Application |
20210324999 |
Kind Code |
A1 |
Baumer; Thomas ; et
al. |
October 21, 2021 |
POLAR CAP-REINFORCED PRESSURE VESSEL
Abstract
The invention relates to a pressure vessel with reinforced pole
caps and a method for producing such a pressure vessel, which
comprises an inner vessel of a cylinder-shaped central part and two
dome-shaped pole caps closing the central part on both sides and an
outer layer wound on the inner vessel for the reinforcement of the
inner vessel against a pressure load, wherein the outer layer
comprises at least one pole cap reinforcement layer and a pressure
vessel reinforcement layer of fiber composite material, wherein the
pole cap reinforcement layer at least partially covers the pole
caps and the pressure vessel reinforcement layer covers the pole
caps and the central part and a contour-stable preform is arranged
as the pole cap reinforcement layer on at least one of the pole
caps, preferably on both pole caps.
Inventors: |
Baumer; Thomas;
(Huckelhoven, DE) ; Middendorf; Christian;
(Aachen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Enrichment Technology Company Ltd. Zweigniederlassung
Deutschland |
Julich |
|
DE |
|
|
Family ID: |
1000003692128 |
Appl. No.: |
16/076768 |
Filed: |
January 31, 2017 |
PCT Filed: |
January 31, 2017 |
PCT NO: |
PCT/EP2017/052017 |
371 Date: |
August 9, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F17C 1/06 20130101; F17C
2201/0109 20130101; F17C 2203/0663 20130101; F17C 2270/0168
20130101; F17C 2203/0604 20130101; F17C 2221/012 20130101; F17C
2221/033 20130101; F17C 2223/035 20130101; F17C 2223/0123 20130101;
F17C 2209/234 20130101; F17C 2203/0619 20130101 |
International
Class: |
F17C 1/06 20060101
F17C001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 12, 2016 |
DE |
20 2016 100 754.2 |
Claims
1. A pressure vessel comprising: an inner vessel from a
cylinder-shaped central part and two dome-shaped pole caps
respectively closing the central part on both sides and an outer
layer wound on the inner vessel for the reinforcement of the inner
vessel against a pressure load, wherein the outer layer comprises
at least one pole cap reinforcement layer and a pressure vessel
reinforcement layer of fiber composite material, wherein the pole
cap reinforcement layer at least partially covers the pole caps and
the pressure vessel reinforcement layer covers the pole caps and
the central part and a contour-stable preform is arranged as the
pole cap reinforcement layer on at least one of the pole caps,
wherein the contour-stable preform is braided from fiber material
with a braiding angle of the fiber material at the pole cap margin
of at least 140.degree., wherein the braiding angle is reduced
significantly towards the pole cap center, wherein one or more
reinforcement threads, with an orientation substantially parallel
to the cylinder axis of the cylindrical central part are braided
into the contour-stable preform.
2-3. (canceled)
4. The pressure vessel according to claim 1, the contour-stable
preform consists of fiber material, stitched onto a drapeable
support material, the fiber material is stitched spirally onto the
support material.
5. The pressure vessel according to claim 4, wherein one or more
reinforcement threads, with an orientation essentially parallel to
the cylinder axis of the cylindrical central part are stitched onto
the support material.
6. The pressure vessel according to claim 4, wherein the support
material is attached with an adhesive layer directly onto the pole
cap.
7. The pressure vessel according to claim 1, wherein the pressure
vessel reinforcement layer features a matrix material and the
contour-stable preform is slid over at least a part of the fiber
composite material, the fiber composite material being wet at this
stage and which is wound over the pole cap of the pressure vessel
reinforcement layer and is fixed in the area of the pole cap by the
matrix material of the pressure vessel reinforcement layer.
8-9. (canceled)
10. A method for the production of a pressure vessel according to
claim 1, comprising an inner vessel of a cylinder-shaped central
part, two dome-shaped pole caps closing the central part on both
sides in each case, and an outer layer wound on the pole caps and
on the inner vessel for the reinforcement the inner vessel against
a pressure load, wherein the outer layer comprises at least one
pole cap reinforcement layer and one pressure vessel reinforcement
layer of fiber composite material, comprising the steps of
producing a contour-stable preform as the pole cap reinforcement
layer for at least one of the pole caps by means of a braiding
method or by means of stitching of fiber material onto a drapeable
support material; application of the pole cap reinforcement layer
on the pole caps, so that the pole cap reinforcement layer at least
partially covers the pole caps application of the pressure vessel
reinforcement layer onto the pole caps and the central part,
wherein the pressure vessel reinforcement layer is applied onto the
pole cap reinforcement layer from the outside.
11. The method according to claim 10, wherein the step of
production of the contour-stable preform comprises a braiding of
the contour-stable preform from a fiber material with a braiding
angle of the preform at a marginal area of the pole cap of at least
140.degree..
12. The method according to claim 11, wherein the braiding
comprises the further step of the additional braiding of one or
more reinforcement threads, with an orientation essentially
parallel to the cylinder axis of the cylindrical central part.
13. The method according to claim 10, wherein the step of
production of the contour-stable preform by means of stitching
comprises a spiral-type stitching of the fiber material onto the
support material, and wherein one or more reinforcement threads
with an orientation essentially parallel to the cylinder axis of
the cylindrical central part are stitched onto the support
material.
14. The method according to claim 10, comprising the additional
step of at least punctual heat-sealing the preform, produced with a
thermoplastic matrix to the pole cap, for the fixation of the
preform to the pole cap.
15. The method according to claim 10, comprising the additional
steps of: curing of the preform with an inner contour adapted to
the pole cap and an outer contour, which is designed in such a way
that the pressure vessel reinforcement layer can be deposited
thereon, wherein the outer contour is designed in such a way that
it constitutes an extension of the central part of the inner vessel
in the marginal area of the pole cap winding up of an inner layer
as a radial winding of the pressure vessel reinforcement layer onto
the central part and directly onto the outer contour in the
marginal up to a stop nose of the preform as a boundary of the
outer contour to be overwound with the pressure vessel
reinforcement layer in the marginal area of the pole cap;
subsequent winding up of one or more outer layers of the pressure
vessel reinforcement layer onto the entire preform.
16. The pressure vessel according to claim 1, wherein the pressure
vessel reinforcement layer covers the pole cap reinforcement layer
and the contour-stable preform is fixed onto the pole cap for the
establishing of the contour stability.
17. The pressure vessel according to claim 16, wherein the
contour-stable preform is produced with a thermoplastic matrix and
is heat-sealed at least punctually with the pole cap of a plastic
material.
18. The pressure vessel according to claim 1, wherein the
contour-stable preform is a cured preform for deposition onto the
pole cap, wherein an inner contour of the contour-stable preform is
adapted to the pole cap and an outer contour of the contour-stable
preform is designed in such a way that the pressure vessel
reinforcement layer can be deposited thereon, wherein the outer
contour is designed in such a way here, that it constitutes an
extension of the central part of the inner vessel in the marginal
area of the pole cap, wherein the pressure vessel reinforcement
layer further comprises a radially wound inner layer, which is
wound as a continuous layer onto the central part and directly onto
the outer contour in the marginal area for the subsequent
overwinding of the entire preform with one or more outer layers of
the pressure vessel reinforcement layer.
19. The pressure vessel according to claim 18, wherein the
contour-stable preform comprises a stop nose as a boundary of the
outer contour, which is overwound with the pressure vessel
reinforcement layer in the marginal area of the pole cap.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a pressure vessel with reinforced
pole caps and to a method for producing such a pressure vessel.
BACKGROUND OF THE INVENTION
[0002] The market for fiber-reinforced pressure vessels of fiber
composite material grows continuously. The increasing extraction of
natural gas and tracking gas requires a storage in pressure
vessels, especially in countries without a corresponding pipeline
network. In addition, there is the automobile sector, which is
highly involved in the development of fuel cell vehicles, in which
the fuel is to be stored in the form of gaseous hydrogen under high
pressure in pressure vessels. Light pressure vessels are desired
for the transport of the pressure vessels, because a transport of
pressure vessels with high vessel weights consumes an unnecessarily
large amount of energy and therefore causes excessively high
transport costs.
[0003] Currently used pressure vessels have a cylindrical central
part, on which pole caps for the closure of the central part are
located on both sides and which are produced, for example, using a
fiber winding method. A liner (inside vessel for the pressure
vessel) is used here, which acts as a winding core on the one hand
and also guarantees the impermeability of the vessel on the other
hand. For the production of the pressure vessel, this liner is then
overwound for reinforcement with fiber composite material, so that
the resulting pressure vessel maintains its stability. Type 3
pressure vessels use a metallic liner of aluminum or steel, whereas
Type 4 pressure vessels use a plastic liner.
[0004] There is the so-called overbraiding method competing with
the winding method, in which dry or pre-impregnated fibers (mostly
carbon fibers) are braided onto the liner. The liner is thereby
braided back and forth until the required fiber reinforcement is
achieved. In the two described production methods, the laminated
structure differs significantly. In the overbraiding process, the
variation possibilities with regard to the fiber angle are much
more limited, because the number of braiding bobbins and the
thickness of the fiber used result in a certain fiber angle, which
can only be varied within small limits. The disadvantages of the
overbraiding process are fiber corrugation and different laminate
quality depending on fiber deposition direction, in particular the
difference, whether the braiding occurs from a small diameter to a
large diameter or vice versa. Fiber corrugation refers to the
redirection of fibers within tissues, for example, in the case of
fiber composite composites, where fiber bundles are woven and held
together by a warp thread, respectively chaining thread. This can
lead to a deviation of the fiber bundles caused by the warp
threads, which leads to a decrease in the fiber-parallel strength
of the tissue.
[0005] In the winding method, a distinction is made between
circumferential winding and axial winding. The circumferential
windings have a fiber deposition angle of 80-90.degree. to the
vessel axis, the axial layers have an angle of 10-70.degree. to the
axis. Theoretically, all winders can be implemented between 0 and
90.degree. in the cylindrical part of the pressure vessel, however,
this makes practically no sense because the tension conditions
dictate a special laminate structure. The laminate structure of the
wound pressure vessel reveals the drawback that in the pole cap
area the reinforcement in the peripheral direction is not possible,
because the thread, that is wound in the peripheral direction,
slides off and only comes to a stop at the liner clamping. This
missing peripheral reinforcement must be compensated for by
corresponding axial windings, because otherwise the vessel will
fail prematurely in the pole cap area. The disadvantage is that the
necessary axial windings are partly only necessary for the pole cap
area and are redundant in the cylindrical area of the pressure
vessel. As a result, especially in the case of long vessels, an
unnecessarily large amount of fiber is processed, which increases
the costs and weight of the vessel.
[0006] It would therefore be desirable if pressure vessels were
available, which can be manufactured with little material
expenditure and have the lowest possible weight.
SUMMARY OF THE INVENTION
[0007] It is therefore an object of the invention to provide a
pressure vessel, that can be produced more cost-effectively while
maintaining the same strength properties.
[0008] This object is achieved by a pressure vessel comprising an
inner vessel of a cylinder-shaped central part and two dome-shaped
pole caps in each case closing the central part on both sides and
an outer layer wound on the inner vessel for the reinforcement of
the inner vessel against a pressure load, wherein the outer layer
comprises at least one pole cap reinforcement layer and a pressure
vessel reinforcement layer of fiber composite material, wherein the
pole cap reinforcement layer at least partially covers the pole
caps and the pressure vessel reinforcement layer covers the pole
caps and the central part.
[0009] The cylinder-shaped pressure vessels comprise a cylindrical
part, here referred to as the central part, which has a circular
cross-sectional surface perpendicular to the cylinder axis. So that
gas can be stored under pressure in this pressure vessel, the
cylinder surfaces of the central part are closed with dome-shaped
lid surfaces. These geometric considerations apply equally to
pressure vessels of an inner vessel and an outer layer wound over
the inner vessel to reinforce the inner vessel, for example, with
an inner vessel of plastic. On the one hand, such vessels have a
very low weight, which, for example, is important for applications
in transport means, and on the other hand gases, such as, for
example, hydrogen, can be stored under high pressure with low loss,
since plastic has very low hydrogen permeability and the required
strength is provided by the outer layer of fiber composite
material. The pressure vessel according to the invention thus
comprises an inner vessel with dome-like lid surfaces, preferably
having a shape deviating from a hemisphere, which has a stronger
curvature in the lid marginal area adjacent to the cylindrical
central part of the inner vessel compared to that of a hemisphere
surface, while the central area of the lid surface has a smaller
curvature compared to that of a hemisphere surface. Such a
particularly suitable dome-shaped lid surface is also referred to
as isotensoid. An isotensoid thereby refers to a form, which in an
outer layer of a fiber composite material wound on top of it,
produces a constant tension in the fibers at all points of the
fiber path. The term "cover" refers to the applying of the pole cap
reinforcement layer and the pressure vessel reinforcement layer to
the inner vessel from the outside.
[0010] In this case, the fiber composite material generally
consists of two main components, in this case fibers, embedded in a
matrix material that produces the solid bond between the fibers.
The fiber composite material can thereby be wound and/or braided
from one or more fibers, wherein the fiber(s) is/are wound tightly
in contact with each other and/or is/are interwoven. This creates a
fiber layer on which the fibers are wound and/or braided in further
fiber layers, until the fiber composite material has the desired
thickness and constitutes a corresponding outer layer with this
thickness. In one embodiment, the outer layer comprises first and
further fibers, for example, second fibers, in multiple fiber
layers. The composite gives the fiber composite material
higher-quality properties, such as, for example, high strength than
either of the two individual components involved could provide. The
reinforcement effect of the fibers in the fiber direction occurs
when the elasticity modulus of the fiber is greater in the
longitudinal direction than the elasticity modulus of the matrix
material, when the elongation at break of the matrix material is
greater than the elongation at break of the fibers and when the
break strength of the fibers is greater than the break strength of
the matrix material. Fibers of all kinds can be used, such as, for
example, glass fibers, carbon fibers, ceramic fibers, steel fibers,
natural fibers or synthetic fibers. Duromers, elastomers or
thermoplastics can be used as matrix materials, for example. The
material properties of the fibers and matrix materials are known to
the person skilled in the art, so that the person skilled in the
art can select a suitable combination of fibers and matrix
materials for the production of the fiber composite material for
the respective use. In this case, individual fiber layers in the
fiber composite area can comprise a single fiber or several
identical or different fibers.
[0011] Due to the fact that only the pole caps comprise a pole cap
reinforcement layer, which, however, does not extend over the
central part and that the strength of the pressure vessel in the
central part can be achieved solely by the pressure vessel
reinforcement layer, which is formed by means of a fiber composite
layer optimized for the geometry of the cylindrical central part
(fiber layers in circumferential direction and axial direction at a
ratio of 2:1), the wrapping of the central part with a fiber
composite layer optimized for the geometry of the pole caps
(additionally axially aligned fiber layers) is avoided.
[0012] The pressure vessel according to the invention thus requires
less fiber composite material for producing the outer layer as a
wrapping of the inner vessel, in order to nevertheless have the
same strength as other pressure vessels. The pressure vessel
according to the invention can thus be produced more
cost-effectively with the same strength properties.
[0013] These advantages can be achieved, for example, by means of a
winding technology and the use of a so-called preform, which is
placed over the pole caps.
[0014] In this case, a contour-stable preform is arranged as pole
cap reinforcement layer on at least one of the pole caps,
preferably on both pole caps. The preform is a textile fiber
preform blank that is applied to the pole caps before or during the
winding of the pressure vessel reinforcement layer and reinforces
these in circumferential direction. The preform can thereby be
produced by means of braiding methods or by means of a so-called
"fiber placement method" and applied to the pole cap. The term
"contour-stable" here refers to the preform having sufficient
intrinsic stiffness, so that it is not displaced or compressed
during later overwinding.
[0015] In one embodiment, the contour-stable preform is a
contour-stable preform which is braided from fiber material and has
a braiding angle of the fiber material at the pole cap margin of at
least 140.degree., preferably at least 150.degree., particularly
preferably at least 160.degree.. The braiding angle is the angle
between the intersecting, respectively crossing fibers whose angle
bisector is essentially parallel to the cylinder axis of the
cylindrical central part. The term "in essence" refers to maximum
deviations of .+-.5.degree. from the stated value. The term
"meshwork" (a braided preform is a preform of fibers or fiber
meshwork intersecting with a braiding angle) thereby refers to the
product from the interlocking of at least two fibers of flexible
material in order to form a ply of meshwork. However, the preform
as a total meshwork can also comprise several such plies of
meshwork. Therefore, a meshwork cannot be made from a single thread
alone and thus forms the opposite of a wound body. In a ply of
meshwork, the fibers (or threads) intersect at a braiding angle,
wherein fibers (threads) running adjacent to each other alternately
underflow and overflow the crossing fibers (threads) and the
respectively neighboring thread performs the underflowing and the
overflowing in the opposite direction. The meshwork of fiber
material can be produced with different tightness, so that between
the individual fibers there can be a volume varying in number and
size, which, for example, can be subsequently filled by matrix
material. In one embodiment, the meshwork comprises multiple layers
of fibers intersecting in a braiding angle.
[0016] In one embodiment, one or more reinforcement threads, with
an orientation essentially parallel to the cylinder axis of the
cylindrical central part, are braided into the braided preform. The
reinforcement threads are advantageous for the bend load capacity
in the pole cap area. When braiding the preform, so-called
0.degree. standing threads can be easily drawn in as reinforcement
threads, wherein the 0.degree. angle corresponds to an orientation
parallel to the cylinder axis. The term "essentially" refers to
maximum deviations of .+-.5.degree. from the stated value. If a
braiding machine arrangement is selected, which results in a
braiding angle in the marginal area of the pole cap of
approximately 160', then a nearly optimal fiber composite material
in a ratio of 2:1 (radial:axial) is produced with the 0.degree.
standing threads, which corresponds to the stress according to the
boiler formula. The braiding angle varies in the pole cap area in a
direction of the pole cap center, according to the distance
relative to the cylinder axis, which, however, is unproblematic in
the event of a decreasing tension. The pole cap reinforcement layer
constructed in this way avoids the fiber corrugation and different
laminate quality depending on a fiber deposition direction
(difference between braiding from a small diameter to a large
diameter or vice versa). For example, carbon threads can be used as
reinforcement threads.
[0017] In one embodiment, the contour-stable preform consists of
fiber material stitched onto a drapeable support material,
preferably the support material is a mat. The term "drapeable"
refers to the ability to adapt to a spatial shape. By stitching,
the fiber material is fixed in its desired orientation. In an
embodiment, the fiber material is stitched spirally onto the
support material.
[0018] In a further embodiment, one or more reinforcement threads,
with an orientation essentially parallel to the cylinder axis of
the cylindrical central part, are stitched onto the support
material. The same applies to this reinforcement threads as already
described above for the reinforcement threads in the braided
preform. For example, the reinforcement threads are likewise
stitched and reinforce the pole cap in the axial direction
(parallel to the cylinder axis)
[0019] In a further embodiment, the support material is attached
directly to the pole cap with an adhesive layer. The adhesive
layer, for example a layer of epoxy resin applied as spray-coat
layer onto the carrier layer, adheres the carrier layer with
stitched-on fiber material firmly to the pole cap after being slid
onto the pole cap and thus prevents a slipping during the
subsequent production steps.
[0020] In a further embodiment, the preform is slid over at least a
part of the still wet fiber composite material, which is wound over
the pole cap, of the pressure vessel reinforcement layer and is
fixed in the area of the pole cap by the matrix material of the
pressure vessel reinforcement layer. The term "wet" refers to a
fiber composite material that has not yet cured, where the matrix
material can still cross-link with the material applied from the
outside. In this case, sufficient matrix material, for example
resin, must be located on the pressure vessel reinforcement layer,
so that the per se dry preform can be immersed with sufficient
matrix material for the contour stability and cross-linking of the
preform. Preferably, the preform is already immersed or impregnated
with a thermoset matrix material. In this embodiment, the pole cap
reinforcement layer is incorporated into the pressure vessel
reinforcement layer as common composite.
[0021] In a further embodiment, the pressure vessel reinforcement
layer covers the pole cap reinforcement layer and the preform is
fixed onto the pole cap in order to produce the contour stability.
As a result, an adhesive layer additionally to be applied can be
dispensed with in the preform. In one embodiment, the preform is
produced with a thermoplastic matrix and is heat-sealed at least
punctually with the pole cap of a plastic material (for example, of
a thermoplastic material). A thermoplastic matrix material enables
the heat-sealing with plastic material.
[0022] In a further embodiment, the preform is a cured preform,
wherein an inner contour of the preform is adjusted to the pole cap
and an outer contour of the preform is designed in such a way that
the pressure vessel reinforcement layer can be deposited thereon,
wherein the outer contour is designed in such a way here that it
constitutes an extension of the central part of the inner vessel in
the marginal area of the pole cap, wherein the pressure vessel
reinforcement layer further comprises a radially wound inner layer,
which is wound as a contiguous layer onto the central part and
directly onto the outer contour in the marginal area for the
subsequent overwinding with further outer layers of the pressure
vessel reinforcement layer, preferably the preform comprises a stop
nose as boundary of the outer contour, overwound with the pressure
vessel reinforcement layer, in the marginal area of the pole cap.
Radial windings refer to the fiber angle in the pressure vessel
reinforcement layer with a fiber direction in the fiber composite
material of close to 90.degree. relative to the cylinder axis of
the central part of the pressure vessel.
[0023] The pressure vessels according to the invention can be used,
for example, as CNG pressure vessels, hydrogen pressure vessels,
breathing air bottles and other pressure vessels.
[0024] The pressure vessel according to the invention, comprising
an inner vessel of a cylinder-shaped central part and two
dome-shaped pole caps closing the central part on both sides in
each case, can be produced, for example, in such a way that an
outer layer is wound onto the pole caps and the inner vessel for
the reinforcement of the inner vessel against a pressure load,
wherein the outer layer comprises at least a pole cap reinforcement
layer and a pressure vessel reinforcement layer of fiber composite
material, in that the pole cape reinforcement layer is applied onto
the pole caps in such a way that it covers these at least partially
and the pressure vessel reinforcement layer is applied to the pole
caps and the central part, wherein preferably the pressure vessel
reinforcement layer is applied onto the pole cap reinforcement
layer from the outside.
[0025] In this case, a contour-stable preform will be arranged as
pole cap reinforcement layer on at least one of the pole caps,
preferably on both pole caps. The preform is a textile fiber
preform blank that is applied to the pole caps before or during the
winding of the pressure vessel reinforcement layer and reinforces
these in circumferential direction. The preform can thereby be
produced by means of braiding methods or by means of a so-called
"fiber placement method" and applied to the pole cap.
[0026] In one embodiment, a contour-stable preform is braided as
pole cap reinforcement layer from a fiber material F1, wherein the
braiding angle FLW of the preform at the pole cap margin is at
least 140.degree., preferably at least 150.degree., particularly
preferably at least 160.degree.. In an additional step, one or more
reinforcement threads, with an orientation essentially parallel to
the cylinder axis of the cylindrical central part, can thereby be
braided in.
[0027] In an alternative embodiment, fiber material can be stitched
onto a drapeable support material, preferably a mat, for the
production of the contour-stable preform (a so-called tailored
fiber placement TFP). In this case, the fiber material can be
stitched spirally onto the support material. Furthermore, one or
more reinforcement threads, with an orientation essentially
parallel to the cylinder axis of the cylindrical central part, can
be stitched onto the support material. The TFP method also offers
the possibility to combine different fibers such as carbon fibers,
glass fibers, or Kevlar fibers with one another in such a way that,
for example, the energy absorption in the pole cap area is
increased, as is required, for example, in the event of a vessel
colliding with a solid surface. The support material can be
attached with an adhesive layer directly onto the pole cap.
Alternatively to the adhesive bonding, the preform can also be slid
over at least a part of the still wet fiber composite material of
the pressure vessel reinforcement layer and can be fixed in the
area of the pole cap by the matrix material of the pressure vessel
reinforcement layer. Alternatively, the pressure vessel
reinforcement layer can be applied onto the pole cap reinforcement
layer in a covering manner, wherein the preform is fixed on the
pole cap in advance in order to produce the contour stability. For
this purpose, the preform can be produced with a thermoplastic
matrix and be heat-sealed at least punctually with the pole cap of
a plastic material.
[0028] Alternatively, the TFP or braiding preform can be
impregnated and cured in a subsequent process, for example by means
of a so-called resin transfer molding (RTM), in a mold with a
thermosetting resin, before the pole cap reinforcement layer
produced in this way is applied onto the pole cap area of the liner
(inner vessel for the pressure vessel). The shape is thereby
designed in such a way that the inner contour of the pole cap
reinforcement layer corresponds to the one of the pole cap of the
liner (inner vessel for the pressure vessel) and the outer contour
constitutes a surface suitable for laying down the axial windings
in accordance with the load.
[0029] In a further embodiment, the outer contour of the pole cap
reinforcement layer can be designed in such a way, as to have the
cylindrical area of the central part of the pressure vessel
initially continued therein in a marginal area of the pole cap as
an extended area, and in this way to allow for facilitated
deposition, drawn into the pole cap area, of the inner plies of the
pressure vessel reinforcement layer in the form of radial
windings.
[0030] In a further embodiment, this preform can be connected to
the pressure port in a form-fitting manner. As a result, together
with the pressure vessel reinforcement layer, which is wound
thereover and, after the curing, makes a connection with the
preform, a high torque from the pressure port can be induced into
the laminate, without straining the connection from the pressure
port to the inner vessel.
BRIEF DESCRIPTION OF THE FIGURES
[0031] These and other aspects of the invention are shown in detail
in the figures as follows.
[0032] FIG. 1: an embodiment of a pressure vessel according to the
invention in a lateral section;
[0033] FIG. 2: an embodiment of a pressure vessel according to the
invention in the region of the pole cap in the lateral section with
a preform of braided fiber composite material;
[0034] FIG. 3: an embodiment of a pressure vessel according to the
invention in the region of the pole cap with a preform of fiber
material stitched onto a support material (a) in a top view of the
pole cap and (b) in the lateral section through the preform;
[0035] FIG. 4: an embodiment of a pressure vessel according to the
invention in the region of the pole cap in the lateral section with
a preform of fiber material stitched onto a support material, which
is draped onto the pole cap;
[0036] FIG. 5: an embodiment of a pressure vessel according to the
invention in the region of the pole cap in a lateral section with a
preform;
[0037] FIG. 6: an embodiment of a method according to the invention
for the production of the pressure vessel according to the
invention, and
[0038] FIG. 7: a further embodiment of a method according to the
invention for the production of the pressure vessel according to
the invention.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0039] FIG. 1 shows an embodiment of a pressure vessel 1 according
to the invention in the lateral section. This pressure vessel 1
comprises an inner vessel 2 of a cylinder-shaped central part 21
and two dome-shaped pole caps 22 respectively closing the central
part 21 on both sides and an outer layer 3 wound on the inner
vessel 2 for the reinforcement of the inner vessel 2 against a
pressure load, wherein the outer layer 3 comprises at least one
pole cap reinforcement layer 31 and a pressure vessel reinforcement
layer 32 of fiber composite material (FVM for short), wherein the
pole cap reinforcement layer 31 at least partially covers the pole
caps 22 and the pressure vessel reinforcement layer 32 covers the
pole caps 22 and the central part 21. The fiber angle FW2 is
thereby an angle of close to 90.degree. to the cylinder axis Z of
the central part, preferably FW2 amounts to more than
80.degree.
[0040] FIG. 2 shows an embodiment of a pressure vessel 1 according
to the invention in the region of the pole cap 22 in the lateral
section with a preform 5 of braided fiber composite material FVM.
This contour-stable preform 5 is arranged as pole cap reinforcement
layer 31 on at least one of the pole caps 22, preferably on both
pole caps 22. In this case, the preform 5 is designed as a
contour-stable preform 51, which is braided from fiber material F1,
with a braiding angle FLW of the fiber material F1 at the pole cap
margin 25 of at least 140.degree., preferably at least 150.degree.,
particularly preferably at least 160.degree.. Towards the pole cap
center 26 the braiding angle FLW is reduced significantly. In this
embodiment, more reinforcement threads 52 are braided into the
braided preform 51, with an orientation essentially parallel to the
cylinder axis Z of the cylindrical central part 21, wherein for the
sake of clarity only two reinforcement threads are shown. The same
applies to the intersecting fibers, where also only a few fibers
are illustrated representative for the remaining fibers.
[0041] FIG. 3 shows an embodiment of a pressure vessel 1 according
to the invention in the region of the pole cap 22 with a preform 53
of fiber material F1 stitched onto a support material 54 (a) in a
top view of the pole cap and (b) in the lateral section through the
preform. The shown preform 53 is arranged as pole cap reinforcement
layer 31 on at least one of the pole caps 22, preferably on both
pole caps 22. In this case, the fiber material F1 can be stitched
spirally onto the support material 54. In this embodiment one or
more reinforcement threads 55, with an orientation essentially in
parallel to the cylinder axis Z of the cylindrical central part 21,
can be stitched onto the support material 54. As shown in FIG. 4b,
the preform 53 comprises an adhesive layer 56 in addition to the
fiber composite material F1, FVM and the carrier layer 54. The
support material 54 is attached with an adhesive layer 56 directly
onto the pole cap. In this case, the reinforcement threads 55 can
slide and thus enable the reshaping to the pole cap contour.
[0042] FIG. 4 shows an embodiment of a pressure vessel 1 according
to the invention in the region of the pole cap 22 in the lateral
section with a preform 53 of fiber material FVM stitched onto a
support material 54, which is draped onto the pole cap 22.
[0043] The pole cap reinforcement layers 5, 51 and 53 of FIGS. 2-4
can be slid over at least a part of the still wet fiber composite
material F2, which is wound over the pole cap 22, of the pressure
vessel reinforcement layer 32 and can be fixed in the region of the
pole cap 22 by the matrix material of the pressure vessel
reinforcement layer 32. For this purpose, the pole cap
reinforcement layers 5, 51 and 53 comprise a thermosetting material
as matrix material, so that a good cross-linking with the pressure
vessel reinforcement layer 32 can be produced.
[0044] Insofar as, on the other hand, the pole cap reinforcement
layers 5, 51 and 53 are to be covered by the pressure vessel
reinforcement layer 32 and the pole cap reinforcement layers 5, 51
and 53 for production of the contour stability are to be fixed on
the pole cap 22, the pole cap reinforcement layers 5, 51 and 53
comprise a thermoplastic material as matrix material, in order to
allow for the production of good heat-sealing to the pole cap,
preferably produced per se of a thermoplastic material.
[0045] FIG. 5 shows a further embodiment of the pressure vessel 1
with the preform 5 as an insertion component for the pole cap 22.
The TFP or meshwork preform 5 was impregnated and cured in a
subsequent process, for example by means of a so-called resin
transfer molding (RTM), in a mold with a duroplastic resin, before
this is applied as pole cap reinforcement layer 31 onto the pole
cap area 22 of the inner vessel 2. The shape of the pole cap
reinforcement layer 31 provided this way is thereby designed in
such a way that the inner contour 5i of the preform 5 corresponds
to that of the pole cap 22 and the outer contour 5a constitutes a
surface suitable for deposition of the axial fiber windings F2 of
the pressure vessel reinforcement layer 32 in accordance with the
load. In this case, the outer contour 5a can be designed in such a
way that in it the central part 21 of the inner vessel 2 is
initially continued in a marginal area 25 of the pole cap 22 as an
extended area, and therefore a deposition of the inner layers F2i
of the pressure vessel reinforcement layer 32 (windings in the
circumferential direction) in the form of radial windings, drawn
into the pole cap area, is facilitated as far as up to the stop
nose 57. In this case, this preform 5 can be positively to the
pressure connection 4 in a form-fit manner. As a result, together
with the pressure vessel reinforcement layer 32, which is wound
thereover and, after the curing, makes a connection with the
preform 5, a high torque from the pressure connection 4 can be
induced into the laminate, without straining the connection from
the pressure connection 4 to the inner vessel 2.
[0046] FIG. 6 shows an embodiment of a method 100 according to the
invention for producing the pressure vessel shown in FIG. 1
comprising the steps of producing 110 a contour-stable preform 5,
51, 53 as the pole cap reinforcement layer 31 for at least one of
the pole caps 22, preferably for both pole caps 22, by means of a
braiding method 112 or by means of stitching 116 of fiber material
onto a drapeable support material 54; the application 120 of the
pole cap reinforcement layer 31 to the pole caps 22, such that the
pole cap reinforcement layer 31 at least partially covers the pole
caps 22; and the application 130 of the pressure vessel
reinforcement layer 32 to the pole caps 22 and the central part 21,
wherein preferably the pressure vessel reinforcement layer 32 is
applied to the pole cap reinforcement layer 22 from the
outside.
[0047] FIG. 7 shows a further embodiment of a method 100 according
to the invention for producing the pressure vessel shown in FIG. 1,
for the production 110 of a contour-stable preform 5 and for the
application 120 of the pole cap reinforcement layer the steps of
curing 140 of the preform 5 with an inner contour 5i adapted to the
pole cap 22 and an outer contour 5a, which is designed in such a
way that the pressure vessel reinforcement layer 32 can be
deposited thereon, wherein the outer contour 5a is thereby designed
in such a way that it constitutes an extension of the central part
21 of the inner vessel 2 in the marginal area 25 of the pole cap
22; as well as the winding 150 of an inner layer F2i as a radial
winding of the pressure vessel reinforcement layer 32 onto the
central part 21 and directly onto the outer contour 5a in the
marginal area 25, preferably up to a stop nose 57 of the preform 5
as a boundary of the outer contour 5a to be overwound with the
pressure vessel reinforcement layer 22 in the marginal area 25 of
the pole cap 22; followed by a winding up 130 of one or more outer
layers F2a of the pressure vessel reinforcement layer 32 onto the
entire preform 5.
[0048] The embodiments shown here are only examples of the present
invention and should therefore not be understood as limiting.
Alternative embodiments, which are considered by the person skilled
in the art, are equally encompassed by the scope of the present
invention.
LIST OF REFERENCE CHARACTERS
[0049] 1 Pressure vessel [0050] 2 Inner vessel [0051] 21
Cylindrical central part of the inner vessel [0052] 22 Dome-shaped
pole caps of the inner vessel [0053] 25 Marginal area of the pole
cap or extended area [0054] 26 Pole cap center [0055] 3 Outer layer
from fiber composite material [0056] 31 Pole cap reinforcement
layer of the outer layer [0057] 32 Pressure vessel reinforcement
layer of the outer layer [0058] 4 Valve/Pressure port [0059] 5
Contour-stable preform as pole cap reinforcement layer [0060] 5a
Outer contour of the preform [0061] 5i Inner contour of the preform
[0062] 51 Contour-stable preform braided from fiber material [0063]
52 Reinforcement threads for meshwork [0064] 53 Contour-stable
preform from fiber material stitched onto a support material [0065]
54 support material [0066] 55 Reinforcement threads for preform
[0067] 56 Adhesive layer [0068] 57 Connection nose for the pressure
vessel reinforcement layer [0069] 100 Pressure vessel according to
the invention [0070] 110 Production of a contour-stable preform
[0071] 112 The production by means of a braid method [0072] 114
Additional braiding of one or more reinforcement threads [0073] 116
The production by means of stitching [0074] 118 Punctual
heat-sealing of the preform with the pole cap [0075] 120
Application of the pole cap reinforcement layer onto the pole caps
[0076] 130 Application of the pressure vessel reinforcement layer
onto the pole caps [0077] 140 Curing of the preform with an inner
contour adjusted to the pole cap [0078] 150 Winding up of an inner
layer of the pressure vessel reinforcement layer directly onto the
outer contour of the preform in the marginal area [0079] F1 Fiber
or fiber material of the pole cap reinforcement layer [0080] F2
Fiber or fiber material of the pressure vessel reinforcement layer
[0081] F2i Inner layers of the pressure vessel reinforcement layer
[0082] F2a Outer layers of the pressure vessel reinforcement layer
[0083] FW1 Fiber angle in the pole cap reinforcement layer [0084]
FLW Braiding angle in the pole cap reinforcement layer [0085] FW2
Fiber angle in the pressure vessel reinforcement layer [0086] FVM
Fiber composite material of the outer layer, of the pole cap
reinforcement layer and/or the pressure vessel reinforcement layer
[0087] Z Cylinder axis of the cylindrical central part
* * * * *