U.S. patent application number 13/879825 was filed with the patent office on 2013-09-26 for fuel tablet and propellan for a gas generator.
The applicant listed for this patent is Klaus Bernau, Christian Bichlmaier, Sebastian Herler, Michael Niehaus, Thomas Nobach, Sebastian Reichgruber, Siegfried Zeuner. Invention is credited to Klaus Bernau, Christian Bichlmaier, Sebastian Herler, Michael Niehaus, Thomas Nobach, Sebastian Reichgruber, Siegfried Zeuner.
Application Number | 20130247790 13/879825 |
Document ID | / |
Family ID | 44645036 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130247790 |
Kind Code |
A1 |
Bernau; Klaus ; et
al. |
September 26, 2013 |
FUEL TABLET AND PROPELLAN FOR A GAS GENERATOR
Abstract
The invention relates to a propellant pellet for pyrotechnical
safety devices in vehicles, such as airbag modules, belt
tensioners, micro-inflators and igniters. The propellant pellet
according to the invention has a substantially cylindrical shape
and can be obtained by dry injection of a powdered propellant
composition. The pellets have a maximum diameter of 2 mm and
preferably a relative bulk density, defined as ratio of bulk
density of the propellant pellets to the maximum theoretical
density of the propellant composition, of at least 0.5. A
propellant charge, an igniter and an inflator each comprising a
plurality of said propellant pellets are provided.
Inventors: |
Bernau; Klaus; (Soyen,
DE) ; Reichgruber; Sebastian; (Engelsberg, DE)
; Niehaus; Michael; (Schulstr, DE) ; Zeuner;
Siegfried; (Munchen, DE) ; Herler; Sebastian;
(Munchen, DE) ; Bichlmaier; Christian; (Schonberg,
DE) ; Nobach; Thomas; (Waldkraiburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bernau; Klaus
Reichgruber; Sebastian
Niehaus; Michael
Zeuner; Siegfried
Herler; Sebastian
Bichlmaier; Christian
Nobach; Thomas |
Soyen
Engelsberg
Schulstr
Munchen
Munchen
Schonberg
Waldkraiburg |
|
DE
DE
DE
DE
DE
DE
DE |
|
|
Family ID: |
44645036 |
Appl. No.: |
13/879825 |
Filed: |
September 15, 2011 |
PCT Filed: |
September 15, 2011 |
PCT NO: |
PCT/EP2011/004625 |
371 Date: |
June 10, 2013 |
Current U.S.
Class: |
102/530 ;
102/283 |
Current CPC
Class: |
F42B 5/16 20130101; C06B
45/00 20130101; C06D 5/00 20130101; B60R 21/2644 20130101; B60R
21/264 20130101 |
Class at
Publication: |
102/530 ;
102/283 |
International
Class: |
C06D 5/00 20060101
C06D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 2010 |
DE |
10 2010 049 765.7 |
Claims
1. A propellant pellet for use in a safety device for vehicles that
is obtained by dry injection of a powdered propellant composition,
having a substantially cylindrical shape and a maximum diameter of
2 mm, wherein the propellant pellet especially has a relative bulk
density of at least 0.5, defined as ratio of the bulk density of
the propellant pellet to the maximum theoretical density of the
propellant composition.
2. The propellant pellet according to claim 1, wherein the
propellant pellet has a relative bulk density of from 0.5 to
0.7.
3. The propellant pellet according to claim 1, wherein the
propellant pellet has a diameter within the range of 1 to 2 mm.
4. The propellant pellet according to claim 1, wherein the
propellant pellet has a ratio of height to diameter of from 0.2 to
0.8.
5. The propellant pellet according to claim 1, having dimensions of
diameter.times.height ranging from 1.0 mm.times.0.4 to 2
mm.times.1.5 mm, wherein the height-to-diameter ratio amounts to a
maximum of 0.8.
6. The propellant pellet according to claim 5, wherein the
dimensions are within the range of 1.5 mm.times.0.4-0.9 mm.
7. The propellant pellet according to claim 5, wherein the
dimensions are within the range of 2 mm.times.0.4-1.5 mm.
8. A propellant charge comprising a plurality of propellant pellets
according to claim 1, especially as part of an igniter, inflator
and/or actuator.
9. An igniter (14) for use in a safety device comprising a
plurality of propellant pellets according to claim 1.
10. An inflator (10) or actuator for use in a safety device for
vehicles, comprising an igniter (14), at least one combustion
chamber associated with the igniter and a propellant charge (16)
accommodated in the combustion chamber (18) for generating gas,
wherein the propellant charge is provided in the form of a filling
of propellant pellets, wherein the filling comprises propellant
pellets according to claim 1.
11. An inflator (10) or actuator according to claim 10, wherein the
propellant pellets are provided in the filling in a single-mode
distribution.
12. The propellant pellets according to claim 1, wherein the
propellant pellet is adapted for use as at least one of a booster
charge and a propellant charge of at least one of an inflator, a
micro-inflator and an igniter.
13. The propellant pellet according to claim 1, wherein the
propellant pellet is adapted for use in at least one of an advanced
ignition device and an advanced ignition mixture directly
integrated in an inflator propellant.
Description
RELATED APPLICATIONS
[0001] This application corresponds to PCT/EP2011/004625, filed
Sep. 15, 2011, which claims the benefit of German Application No.
10 2010 049 765.7, filed Oct. 29, 2010, the subject matter of which
are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a propellant pellet for
pyrotechnical safety devices in vehicles such as airbag modules,
belt tensioners, micro-inflators, actuators and igniters as well as
to a propellant charge, an igniter and an inflator each of which
includes a plurality of said propellant pellets.
[0003] From WO 01/19760 A2 it is known to control the burn-off time
of inflator propellants via the grain shape and size of the
inflator propellant charges. For booster charges and inflator
propellant charges requiring a short burn-off time usually
propellant granules are used.
[0004] The production of propellant granules is known, for example,
from DE 100 20 291 A1. Generally the relatively high production
costs due to the complex processing steps constitute a drawback of
the use of propellant granules. The production of granules can be
performed according to different methods such as e.g. breaking of
compacts, extruding or pressing of moist masses, build-up
agglomeration or spray granulation. Basically a distinction can be
made between dry or wet processes.
[0005] In the dry processes already manufactured compacts (e.g.
pellets) are broken again and the fragments obtained are screened
according to the desired granule size. Granules manufactured in
this way usually have an inhomogeneous and irregular grain shape.
In particular those granules are little abrasion-resistant, because
the edges, corners and points are easily broken upon mechanical
wear.
[0006] Granules manufactured by wet processes basically have the
drawback of the use of solvents and binders. The former have to be
removed again in a complicated manner in additional process steps,
the latter are undesired formula ingredients which affect the
burn-off (e.g. the gas composition) of the propellant.
[0007] Propellant granules further have a distribution of grains of
different grain size and grain surface. Therefore, already during
the transport of propellant granules a segregation of the larger
grains from smaller granule grains can take place. Also when
filling inflators with propellant granules such segregation and
thus a scattering of the inflator output can occur, because the
larger granule grains flow more rapidly than small grains. A
segregation of the propellant granules finally can occur also in
the mounted state of the inflator over the operating time of the
vehicle so that the inflator output can vary over time.
[0008] Moreover adjusting the ballistic properties of propellant
granules manufactured by breaking larger compacts is possible to a
limited extent only, because the breaking operations resulting in
granules are not exactly defined. Also by screening the grain
surface and thus the ballistic behavior can only be adjusted in a
very complex manner, as the granule grains usually have an
irregular shape. Thus it is imaginable that ballistic results of
individual inflators are broadly scattered also within a
manufacturing batch. Moreover granules manufactured in this way are
very sensitive to mechanical load due to the very irregular
geometry and therefore exhibit low abrasion resistance. Thus the
ballistic properties vary strongly upon loads as they occur during
transport, for instance.
[0009] Although the granule grains manufactured by so called
build-up agglomeration in a fluidized bed generator, for example,
are rounder and thus better to screen, these propellant granules
only have a low density and thus a lower volume-related gas yield
than compacted granules, however.
[0010] Finally the grain sizes cannot be specifically adjusted
during granule manufacture. Rather, the desired fractions have to
be screened. Therefore during granule manufacture a higher
proportion of waste always accumulates. Filling the inflators with
propellant granules is difficult, too, and requires long cycle
times because the flowability of granules is rather poor.
[0011] The manufacture of propellant compacts having a cylindrical
base shape can take place by extruding suitable masses in wet
process and cutting the extruded propellant strand. In this way
propellant compacts having a diameter of 1 mm to approx. 5 mm can
be obtained. The addition of a binder required to manufacture the
extruded propellant compacts can be detrimental to the ballistic
properties of the propellant composition.
[0012] When cutting the still soft extruded product, fraying of the
cutting faces is always resulting that has strong and
non-controllable effects on the ballistic properties of the thus
manufactured propellant pellets mainly in the case of small
diameters. When the extruded product is first dried and then cut,
the propellant compacts are pre-damaged due to the strong shear
forces occurring during cutting. Micro-fissures or bursts of the
propellant occur. In some cases it can be necessary due to the
propellant specifications to cut the extruded product to a height
ranging from 0.4 mm to 1 mm. Those dimensions can hardly be
manufactured in a reproducible manner by an extruded propellant
strand. In these cases the ballistic properties of the propellant
therefore either can no longer be controlled or else can be
obtained only with great scattering in the pressure/time
curves.
SUMMARY OF THE INVENTION
[0013] The present invention is based on the object to provide a
propellant pellet for pyrotechnical applications in safety systems
for vehicles which can be manufactured in an inexpensive and safe
way and permits a reproducible control of the burn-off behavior.
Furthermore the object underlying the invention is to provide a
propellant charge, an igniter, an actuator and an inflator or
actuator including a number of such propellant pellets.
[0014] To achieve these objects, concerning the propellant pellet
in accordance with the invention a propellant pellet according to
claim 1 is provided. Furthermore, concerning the propellant charge
a propellant charge in accordance with the invention according to
claim 8 is provided, concerning the igniter an igniter in
accordance with the invention according to claim 9 is provided,
concerning the inflator or the actuator an inflator or actuator in
accordance with the invention according to claim 10 is
provided.
[0015] The subject matter of the invention further is the use of
the propellant pellets according to the invention in safety devices
of vehicles such as an airbag module, a belt tensioner, a
micro-inflator, an advanced ignition means and a pyrotechnical
igniter.
[0016] Advantageous embodiments of the invention are stated in the
subclaims.
[0017] The manufacture of propellant pellets by injecting
propellant powders is known, for instance, from the afore-mentioned
WO 01/19760 A2 and DE 100 58 934 A1. However, in applications for
vehicle restraint means usually only propellant pellets having a
relatively large diameter are used.
[0018] In accordance with the invention, however, a substantially
cylindrical propellant pellet for use in a vehicle safety device is
provided which can be obtained by dry injection of a powdered
propellant composition and has a maximum diameter of 2 mm, the
propellant pellet especially having a relative bulk density of at
least 0.5, preferably 0.5 to 0.7.
[0019] The relative bulk density is defined to be the ratio of bulk
density determined as mass of the propellant pellets related to the
bulk volume to the maximum theoretical density of the propellant
composition. The bulk density relates to values established in a
100 ml measuring glass having a diameter of 30 mm. Measuring takes
place by filling the pellets to the filling line and subsequent
weighing without shaking, blowing or other compacting of the bulk.
The maximum theoretical density (tmd) is established from the
crystal densities of the respective ingredients of the composition.
Due to the reference to the maximum theoretical density, the amount
of the relative bulk density is independent of the respective
propellant composition and is substantially determined by the
geometry of the propellant compact.
[0020] Especially preferred, the relative bulk density is within
the range of from 0.54 to 0.6, preferably within the range of from
0.56 to 0.59.
[0021] The propellant pellet according to the invention has a
maximum diameter of 2 mm. Preferably the diameter is within the
range of from 0.8 mm to 2 mm, further preferably within the range
of from 1 mm to 2 mm and especially preferred within the range of
from 1.5 mm to 2 mm.
[0022] The ratio of height to diameter (hid) of the propellant
pellets according to the invention preferably is within the range
of from 0.2 to 0.8.
[0023] The dimensions (diameter.times.height) of the propellant
pellets according to the invention preferably is within a range of
from 1 mm.times.0.4 mm to 2 mm.times.1.5 mm, the ratio of height to
diameter being not more than 0.8.
[0024] In these ranges the propellant pellets can be manufactured
inexpensively having perfectly reproducible ballistic properties.
Especially preferred are propellant pellets having dimensions in
the range of from 1.5 mm.times.0.4-0.9 mm and 2 mm.times.0.4-1.5
mm.
[0025] The propellants used can be all propellants known in prior
art for pyrotechnical restraint means as described, for example, in
WO 01/19760 A2.
[0026] The invention also comprises a propellant charge and an
igniter each of which comprises a plurality of afore-described
propellant pellets according to the invention.
[0027] The propellant pellets according to the invention can be
advantageously used as substitute for conventional propellant
granules, especially for booster charges in pyrotechnical inflators
and as propellants having a short burn-off time in micro-inflators,
for example. Furthermore, the propellant pellets according to the
invention can be used in igniters in a safety device, as for
instance in a pyrotechnical inflator for inflating an airbag to
protect a vehicle occupant in the case of accident. Equally the
propellant pellets according to the invention can be incorporated
in an actuator which props up the hood of a vehicle in the case of
accident so as to provide an optimized crush zone for an impact of
a pedestrian.
[0028] After complex tests applicant finally has succeeded in
reducing the manufacturing costs of the propellant pellets
according to the invention considerably below the costs of the
known granule manufacture inter alia as the complicated screening
and classifying processes and the additional drying step can be
dispensed with for wet-manufactured granules. Moreover, also the
working safety is increased because for the pellet manufacture no
breaking operations have to be carried out and no highly
inflammable fine dust accumulates.
[0029] The propellant pellets according to the invention have a
reproducible geometry and thus an easily reproducible burn-off
behavior. Therefore the pellets according to the invention can be
easily and inexpensively adapted to the desired output requirements
and customer specifications for inflators, for instance by
variation of height and/or diameter. Even in comparison to the
granules manufactured of compacts the bulk density of the
propellant pellets according to the invention is higher. With equal
propellant weight thus lower volumes of combustion chambers can be
employed. For instance, for pellets having a diameter of 1.0 mm and
a height of 0.5 mm made of a mixture of 60.8% by weight of
guanidine nitrate, 36.7% by weight of potassium perchlorate and
2.5% by weight of additives a bulk weight of 1.01 g/cm.sup.3 was
measured, whereas from pellets injected before of the same
composition which were subsequently broken and screened into
granules having a grain distribution between 0.5 mm to 1.2 mm
merely a bulk weight of 0.87 g/cm.sup.3 was obtained. This
corresponds to an increase in the bulk weight of approx. 16%.
[0030] The ballistic tests with the propellant pellets according to
the invention result in a relatively narrow scattering, because the
grain size distribution in the propellant charge with injected
pellets of defined grain size can be adjusted within narrow limits
and can be better reproduced compared to the irregular granule
grains. Thus the ballistic properties of the propellant charges can
be adjusted to be variable and reproducible also by a variation of
the grain size distribution by the use of pellets of different
size.
[0031] Tests have resulted in the fact that when using the
propellant pellets according to the invention the inflator output
remains stable over the operating time of the inflator (>15
years), because the pellets are not segregated or irregularly
reduced by vibration and thus enlarge the surface. Therefore the
burn-off characteristic does not vary. Even during transport of the
propellant pellets according to the invention to other locations of
the inflator manufacture no segregation and thus no detrimental
variation of the bulk composition does occur.
[0032] Finally the propellant pellets according to the invention
can be dosed more easily and within a shorter cycle time into the
inflator due to the better flowing behavior. The filling of the
inflator with the propellant pellets according to the invention is
carried out in a by far more homogenous manner than with granules,
because even during dosing no segregation occurs so that ballistic
results that can be better reproduced are obtained. Moreover, fine
dust is prevented from forming, because the pellets used are by far
more abrasion-resistant that the granules used so far.
[0033] Compared to extruded propellant compacts, the propellant
pellets according to the invention also have a higher density while
exhibiting the same composition. Therefore also the bulk density of
the propellant pellets according to the invention is higher than
the bulk density of the propellant compacts manufactured by
extrusion while having equal dimensions and thus equal packing
density, i.e. parts per volume unit.
[0034] For example, for a wet-extruded compact having geometry of
3.9.times.4 mm of 45% by weight of guanidine nitrate, 50% by weight
of basic copper nitrate and 5% by weight of guar gum a density of
the propellant compact of 1.7 g/cm.sup.3 is found by experiment.
The density of the extruded propellant compact thus only reaches
84% of the maximum theoretical density (tmd) of 2.03 g/cm.sup.3.
The density of dry-injected propellant pellets having the same
propellant composition, on the other hand, usually reaches up to
99% of the maximum theoretical density. Hence for the
afore-mentioned composition a bulk density that is by 18.3% higher
compared to the extruded compacts can be achieved with dry-injected
propellant pellets. This allows for a reduction of the combustion
chamber in the same magnitude.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Further features and advantages of the invention are obvious
from the following description of preferred embodiments with
reference to the enclosed drawings which are not meant to be
limiting. In the drawings
[0036] FIG. 1 shows the schematic representation of an
inflator;
[0037] FIG. 2 shows a diagram illustrating the relative bulk
density of the pellets according to the invention against the
pellet diameter; and
[0038] FIG. 3 shows the representation of pressure/time curves of a
defined propellant for different pellet sizes.
DESCRIPTION
[0039] The components of the inflator 10 illustrated in FIG. 1 are
known per se. The inflator 10 has an external housing 12 in which
an igniter 14 is inserted. In the case of accident the igniter is
activated and ignites a propellant charge 16 accommodated in a
combustion chamber 18 associated with the igniter 14.
[0040] According to the invention, the propellant charge 16
disposed in the combustion chamber is provided in the form of a
filling with the propellant pellets 20 according to the invention
which are represented only schematically but not true-to-scale in
FIG. 1.
[0041] The filling may contain the propellant pellets according to
the invention at least partly, preferably at a proportion of at
least 10% by weight, further preferably of at least 30% by weight,
at least 50% by weight or at least 70% by weight, and especially
preferred it may consist completely of the propellant pellets
according to the invention.
[0042] Particularly preferred the propellant pellets of the
invention are provided in the filling in a single-mode
distribution.
[0043] The propellant pellets according to the invention have a
substantially cylindrical shape and can be obtained by dry
injection of a powdered propellant composition. The pellets have a
maximum diameter of 2 mm.
[0044] The density of the dry-injected propellant pellets
preferably is at least 95% of the maximum theoretical density
(tmd), further preferred at least 97% and especially preferred
between 97% and 99% of the maximum theoretical density.
[0045] The relative bulk density of the propellant pellets
according to the invention is at least 0.5, preferably 0.5 to 0.7,
and further preferred from 0.54 to 0.6. Especially preferred the
relative bulk density is within the range of from 0.56 to 0.59.
[0046] In accordance with a further preferred embodiment, the
propellant pellets of the invention have a diameter (d) of from 0.8
mm to 2 mm. Preferably the diameter ranges from 1 mm to 2 mm and in
an especially preferred manner ranges from 1.5 mm to 2 mm.
[0047] The propellant pellets according to the invention preferably
have a ratio of height (h) to diameter (d) of h/d=0.2 to 0.8.
[0048] It is understood to those skilled in the art that the
afore-mentioned parameters can be freely combined with each
other.
[0049] According to an especially preferred embodiment, the
dimensions of the propellant pellets of the invention range from
d.times.h=1 mm.times.0.4 mm to 2 mm.times.1.5 mm, the
height-to-diameter (hid) ratio amounting to a maximum of 0.8. In
this range the propellant pellets having perfectly reproducible
ballistic properties can be manufactured at low cost. Especially
preferred are propellant pellets having dimensions within the range
of d.times.h=1.5 mm.times.0.4-0.9 mm and 2 mm.times.0.4-1.5 mm.
[0050] In the state of the art frequently cylindrical propellant
pellets having a diameter of 3 mm to 8 mm are used. The
height-to-diameter ratio for these pellets usually is within the
range of from 0.2 to 0.5 for reasons of manufacture.
[0051] FIG. 2 shows a diagram illustrating the relative bulk
density against the pellet diameter with a constant
height-to-diameter ratio (hid). The measurements show that pellets
of smaller diameter (with equal height-to-diameter ratio) have a
higher relative bulk density. Furthermore it could be shown by
experiment that the relative bulk density is increased with a
constant pellet diameter when the pellet height and the pellet
diameter are adapted to each other.
[0052] Since the relative bulk density is only dependent on the
geometry of the propellant compacts, the described interactions are
applicable to all propellant compositions.
[0053] It is directly resulting from the diagram illustrated in
FIG. 2 that by a reduction of the pellet diameter from e.g. 4 mm to
1.5 mm with an h/d ratio of 0.5 a change of the relative bulk
density from approx. 0.51 to 0.54 is obtained. As a result, the
volume of the combustion chamber can be reduced by about 6 percent
so that with the same output, measured as mass of gas per time, the
inflator can be manufactured to be cheaper, lighter and
smaller.
[0054] The pellets according to the invention having a diameter of
e.g. 1.5 mm can also be pressed more easily with a higher
height-to-diameter ratio (hid). For instance, propellant pellets
having a ratio of h/d=0.7 and a diameter of d<2 mm can be easily
realized.
[0055] Compared to a conventional pellet of 4.times.2.2 mm
(h/d=0.55), for a pellet of 2.times.1.6 mm even an increase in the
relative bulk density by 14 percent is resulting. Consequently,
also the combustion chamber volume of the inflator can be reduced
by 14 percent with the same output.
[0056] Further examples are listed in the following table showing a
comparison of the propellant pellets according to the invention to
the propellant pellets used according to the state of the art.
Furthermore, the reduction of volume of the combustion chamber that
is possible by the use of the propellant pellets according to the
invention is indicated.
TABLE-US-00001 TABLE 1 Comparison of different pellet geometries
Relative Volume saving (%) Diameter Height, bulk compared to: mm mm
h/d density 6 .times. 2.2 mm 4 .times. 2.2 mm 3 .times. 1.1 mm 3
1.1 0.37 0.48 23 -9 0 4 2.2 0.55 0.3 36 0 10 6 2.2 0.37 0.39 0 -26
-19 2 1 0.50 0.54 37 2 12 2 1.2 0.60 0.56 43 5 17 2 1.4 0.70 0.58
49 10 22 2 1.6 0.80 0.60 55 14 26 1.5 0.75 0.50 0.54 39 3 14 1.5
0.85 0.57 0.55 42 5 16 1.5 0.95 0.63 0.56 45 7 18 1.5 1.05 0.70
0.58 48 9 21
[0057] FIG. 3 illustrates a diagram including an exemplary
representation of the pressure/time curves of a defined propellant
comprising 36.7% by weight of potassium perchlorate, 60.8%) by
weight of guanidine nitrate and 2.5% by weight of additives for
different pellet sizes. This is compared to pellets having
dimensions of 3.times.1 mm and 2.times.1.55 mm. In this example the
relative bulk density of the propellant pellets increases from
about 0.46 to about 0.59. As a consequence, a volume saving of the
combustion chamber of approx. 28 percent can be achieved.
[0058] The example shows that by using smaller pellets having a
larger height-to-diameter ratio the changed ballistics can be
compensated and the same inflator output, measured as gas mass per
time, can be achieved.
[0059] Another possibility of reducing the combustion chamber
volume is to use a propellant that burns more slowly to adapt the
ballistic performance. In this case, also major changes of the
pellet geometry can be made and for example pellets having a
diameter of 6 mm can be replaced with pellets having a diameter of
2 mm. In this way great savings of the combustion chamber volume
can be achieved while the ballistic performance remains constant,
as is shown in the foregoing table.
[0060] The propellant pellets according to the invention can be
manufactured in accordance with the methods known in the state of
the art by dry injection of powdered propellant compositions,
preferably in rotary pellet presses known per se.
[0061] The inventors now have found that by optimizing the process
parameters also pellets having a diameter of <2 mm to preferably
about 0.8 mm can be manufactured.
[0062] For sufficient filling of the matrices at high extruding
speed initially a propellant powder of appropriate grain size is
provided. The exact grain size distribution depends on the matrix
size and on the flow behavior of the respective propellant
composition.
[0063] Furthermore the shaking parameters of the pellet press are
configured so that a rapid flow of the propellant powder into the
matrix is ensured.
[0064] The propellant pellets according to the invention can be
used in all pyrotechnical restraint systems. Preferred is the use
in inflators for airbag modules, belt tensioners, micro-inflators
and igniters, especially in the form of a gas-generating propellant
charge and/or booster charge.
[0065] Further preferred is the use in an advanced ignition device
for inflators and/or as advanced ignition mixture directly
integrated in the gas-generating propellant charge.
* * * * *