DE2541724A1 - METHOD FOR GENERATING GASES FROM CHEMICALS - Google Patents

Description

A. GRÜNECKER H. KINKELDEY

URGENT

OC / 1 Ί *> / ^W STOCKMAiR

/ Jj UI / £ * ^ OR-Ma-AnE (CALTFCH

K. SCHUMANN

DR REFt ΝΚΓ. ■ DIH _- * HYS

P. H. JAKOB

DIR.- ING

G. BEZOLD

DR. HfA MAT ■ KTL-CHEM

MUNICH

MUNICH 22

MAXIMUM INITIATIVES 43

18th September 1975

NISSAIT MOTOR COiIPANI, LTD.

No. 2, Takara-machi, Kanagawa-ku,

Yokohama City / Japan

Method of generating gases from
Chemicals

The invention "deals with the development of a powerful gas generating system and in particular with a method for producing a gas-emitting device. In the method according to the invention is of Having made use of a solid chemical, polygamy is exothermic added with the development of gaseous reaction products. These gaseous reaction products are suitable

609817/0766

for inflatable safety devices. Furthermore, according to the invention made use of a granular material which removes heat from the gaseous reaction products or in other words, heat is absorbed by the gaseous reaction products. The invention is particularly concerned however, an improved method for introducing such. Eornmaterials into the housing of the gas generating device to propose.

Some embodiments of conventional security or Life saving devices, such as lifeboats or inflatable safety bags for the protection of Vehicle occupants from injuries in traffic accidents are provided with a gas generating device in which a solid chemical is contained. With this solid chemical it is usually a pyrotechnic compound that is capable of burning or decomposing is to generate large amounts of gaseous reaction products within a very short time. A gas developer this type usually contains a heat-absorbing material, which helps the temperature of the reaction gases before the outflow is reduced. The heat-absorbing material is also expected to absorb solids, which are contained in the reaction gas. In such a gas generator, the heat absorbing material plays one very important role, because the facilities into which the reaction gas is passed and at which, for example, only Lifeboats and safety bags are usually made of a material with only low heat resistance. Such materials are usually synthetic fiber fabrics, rubber or synthetic resin sheets. Such a material is of course very endangered by that formed at a very high temperature Reaction gas, which contains a considerable amount of solids

60981 7/0766

contains.

As the heat-absorbing material, some conventional gas generators use a layer of a plurality of made of carbon steel, stainless steel, copper or existing brass wire shields are used. However, it is more common to use grains or granules of a material with relatively high thermal conductivity and high specific To use heat. Examples of such materials are iron and aluminum, a metal oxide such as aluminum oxide and magnesium oxide and an inorganic compound, as called for example silicon carbide. The granules are in the gas generator with the formation of a Column or layer arranged in such a way that the reaction gas passes through this layer before it exits the Gas generator reached. The packing layer of the granulated heat-absorbing material is essentially the wire mesh layer consider for the following reasons:

1) It is possible to select a material with a comparatively large specific heat and the heat capacity depending Volume unit of the granules arranged in the packing layer is larger than when using wire mesh because of the smaller number of cavities.

2) Because of the narrowness and intricacy of the passageways formed between each granule, both the reduction of the gas temperature as well as the trapping of the solids with higher efficiencies leads.

3) Granules are cheaper and can be made at lower prices Costs are brought into the gas generator.

609817/0766

The granular heat-absorbing material must be as tight as in a chamber formed in the housing of the gas generator possible to be packed in order to be able to act according to its task, with of course the reaction gas still the Must have the possibility of passage. The granules are currently being processed using the so-called "tapping method" introduced into the gas generator, in which the housing is gently shaken or shaken after the Granules have been poured into the casing.

Conventional gas generators, which the heat-absorbing packaged in this way Containing granules have certain disadvantages. In practical operation of the gas generator it turns out that that the temperature of the gas generated is considerably above the expected temperature, although the gas generating The chemical and the heat-absorbing granules have been closely monitored. An unexpected increase in However, gas temperature is not just for the inflator harmful, but can also be dangerous for the users of such a facility, which is particularly to be feared is when the gas generator is used to inflate the above-mentioned safety bag for automobile passengers will. An increase in the gas temperature leads to an increase in the inflation pressure prevailing in the sack, although the amount of gas based on normal conditions, is kept constant. The consequence of this is that the safety bag does not provide the automobile traveler with the help of a suitable padding or cushion effect protects, since too high a gas pressure in the sack has the consequence that the vehicle occupant is thrown back and injured when it is moved against the sack at high speed in an accident situation. The extent of the deviation of the Gas temperature from the expected temperature becomes even more apparent if the gas generator mechanical vibrations and / or Hitting of a certain size and duration is suspended. Such mechanical vibrations, however, occur during transport

609817/0766

in the vehicle. In extreme cases, the gas temperature can be twice as high as expected, which can even affect the safety bag can burst.

Are the heat-absorbing granules in a much larger than the nominal amount on which the design is based used to prevent an insufficient temperature reduction in this way, so necessarily increase the dimensions of the gas generator. However, it is extremely important that the size of the gas generator be so small be kept as possible, since the device to which the gas generator belongs, often only takes up a small amount of space Has.

It can be assumed that the mentioned deviations of the heat-absorbing material from the underlying Absorbance is primarily due to the fact that it is not possible with the help of the aforementioned "tapping process" is to achieve a satisfactorily dense packing layer.

The present invention relates to the manufacture of a gas generator having a hot gaseous reaction product generating chemical and a granulated heat absorbing material to lower the temperature thereof Reactive gas before it is used for inflation. It is an aim of the invention to provide an improved one To create a method for introducing or charging the granular material into the housing of the gas generator. This The method should be able to ensure a precise packing position of the granules and, in this way, the deviations in view to improve the heat and the effectiveness of the absorption of solids even when the gas generator subjected to vibrations and / or sudden shocks before being actuated; .

609817/0766

According to the invention, granules of a heat-absorbing Material is poured into a chamber formed in a housing of a gas generator to create a loosely packed Then a compressive force is applied to the layer and across the entire area to form layer with only one free surface The free surface is distributed so that the granules are compacted- Preferably the compressive force is applied Pressing the granules with a flat punch applied to the free surface of the loosely packed layer acts. The total amount of granules to be encased in the housing is preferably divided into a large number of equal parts divided and each part is pressure treatment before filling subjected to another part.

Further features, advantages and details of the invention emerge from the following description of the exemplary embodiment with reference to the drawing. In this show:

Fig. 1 is a section through a with a gas generating A conventional gas generator provided with a composition and a granulated heat-absorbing material,

2 shows a section through a further conventional gas generator, which works in principle in the same way, but has a different construction than the gas generator from Fig. 1,

3 shows the device according to FIG. 1 from the same point of view, but during a not yet finished state during a pressing process according to the invention for compacting the granulated heat-absorbing material, and

60981 7/0766

FIG. 4 shows a representation of the pressing process comparable to FIG. 3, but on the device according to FIG. 2.

A gas generator 10, as shown in Fig. 1, is used for Release a reaction gas from its cup-shaped Housing 12 in the radial direction with the aid of a plurality of openings 14 in the outer wall 16 of the housing are trained. The open end of the cup-shaped housing 12 is closed by a cover plate 18 and an electrically actuated ignition or trigger device 20 is through a threaded opening 22, which is arranged in the middle of the vessel bottom, accommodated in a sealed manner in the housing 12. A cylindrical partition wall 24 is fixedly and concentrically arranged within the housing 12 to form a cylindrical combustion chamber in the housing 26 and an annular cooling chamber 28, the latter between the partition wall 24 and the housing outer wall 16. In the partition wall 24 is provided with a plurality of radial openings 30 which communicate between the combustion chamber 26 and the cooling chamber 28 create. A gas generating compound such as a mixture of potassium perchlorate and sodium azide, is introduced into the combustion chamber 26 in the form of a plurality of pellets 32. These Pellets are made using a cylindrical wire screen 34 prevented from touching the perforated partition wall 24. The cooling chamber 28 is convenient with granules 36 from one inert and heat-absorbing material filled, in which it is primarily the aforementioned metals or Oxides or silicon carbide. The outer surface of the partition wall 24 and the inner surface of the wall 16 are clad with wire mesh layers 38 or 40, a passage of the granules 36 through the openings 30 and 40 to prevent. A filter layer 42 is sandwiched between the outer wire mesh 40 and the wall 16.

6098 17/0766

In operation, the pellets 32 are the gas-generating Compound ignited by actuating the igniter 20 and then burn by way of a self-sustaining Combustion producing large amounts of reactive gas. The reaction gas leaves the combustion chamber 26 through the wire screen 34 and the openings 30 and passes through the wire mesh 38 into the cooling chamber 28. The granules 36 in the Cooling chambers 28 force the reaction gas to flow through very narrow and intricate passages, the are formed as cavities or voids within the granules 36. As he passes through these narrow ones and labyrinthine flow channels, the reaction gas gives a considerable amount of its heat through heat exchange with the granules 36.

At the same time, most of the solid particles contained in the reaction gas are absorbed by the granules 36. Of the unabsorbed residue of solid particles is absorbed in the filter layer 4-2 before the cooled gas enters the housing 12 Help of the radial openings 14- leaves. The one so chilled and purified gas is used to inflate a safety device, such as a life-saving device for the Shipping or a safety bag to protect vehicle occupants from injuries in vehicle collisions, used.

FIG. 2 shows another type of conventional gas generator 4-4, which in principle is the device shown in FIG equals. In the gas generator of FIG. 2, however, a reaction gas is discharged from the cup-shaped housing 12A, which takes place in the axial direction with the aid of openings 4-6 which are formed in a cover plate 18A. The inside of the case 12A is with the help of a circular partition wall 4-8, which is provided with a plurality of passage openings 50,

60981 7/0766

divided into two cylindrical sections. The lower section 26A contains Pelletson 30 from a gas generating Device and serves as a combustion chamber, while the upper section 28A with granules 36 from the heat-absorbing Material is filled and serves as a combustion chamber. The lower side of the partition wall 48 is secured with the aid of a wire screen 52 insulated against the pellets 32 and the top side is with a Wire mesh 54 disguised to protect the granules 36 from to fall through the openings. The igniter 20 is in the same manner as that in Pig. 1 shown Device provided in housing 12A.

The operation of this gas generator 44 is similar to the operation of the device shown in Pig-1 with the difference that the cooled and cleaned gases exit the housing 12A in the axial direction through the openings 46. The two Gas generator types 10 and 44 are essentially based on the made same way. First, the partition wall 24 or 48 in the housing 12 or 12A together with the wire shields 34 and 38 (or 52 and 54) arranged. At the device 10 according to Pig. 1, the wire mesh 40 and the filter layer 42 are also mounted at this time of assembly. Then the granules 36 are filled into the cooling chamber 28 or 28A and the cover plate 18 or 18A (together with the pilter 58 and the wire screen 56) is attached to the housing 12 or 12A attached to the upper end, for example by welding along the entire circumference of the cover plate 18 or 18A can be done. The pellets 32 are introduced into the combustion chamber 26 or 26A through the threaded opening 22, whereupon the ignition device 20 is finally installed.

The granules 36 must be tightly packed in the respective cooling chamber be arranged in order to achieve the desired heat exchange and the desired absorption of pest particles with a high

609817/0766

In the following, the description will be based on from Fig. 1 continued, as far as the devices 10 and 44- coincide. According to the state of the art the granules 36 are packed in the cooling chamber 28 in that the housing 12 after the granules have been filled into the cooling chamber 28 is jolted or shaken. The total amount of granules 36 inserted into a single device 10 has been previously divided into several parts and a shaking or shaking is subsequent after filling made of each of the subsets mentioned. To this end, the open end of the housing 12 is provided with a closed with a suitable lid. If, with the help of the shaker, the proportion of granules 36 filled in is sufficient has settled, then the next part of granules 36 is in the cooling chamber 28 and on the deposited granules 36 introduced, on which ... a similar vibrating and shaking treatment. The introduction of the granules 36 into the cooling chamber 28 is completed when the The height of the granules 36, which are jogged together as far as possible, is almost equal to the effective depth of the cooling chamber 28, only a little space has remained free for the arrangement of the cover plate 18.

Despite these arduous procedures for densely packing the granules 36, the layer of granules formed in the cooling chamber 28 is not always able to achieve a satisfactory absorption of heat and solids from the passing through To ensure reaction gases. The reaction gas that has escaped from the gas generator then remains in particular on a dangerously high temperature when holding a large amount of. Solids when the gas generator 10 is on a transport vehicle conveyed and subjected to mechanical vibrations and / or sudden vibrations prior to its actuation will.

60981 7/0768

In one test, the gas generator 10 was subjected to a variety of vibration and impact tests, one of which is 60 hours of continuous vibration at a frequency of Provide 15 Hz and an acceleration of ± 4-G. Afterward the generator was dropped ten times from a height of 5 meters onto a concrete floor, whereupon the gas generator in conjunction with a conventional nylon safety bag to protect vehicle occupants. Included it was observed that the temperature of the reaction gas exiting from the gas generator 10 in the gas generator examined was extremely high and that the gas pressure in the bag was twice as high as with an otherwise similar safety device, However, in which the gas generator 10 is not subjected to vibration and impact stress tests had been. As a result, the safety bag burst during a few attempts.

The inventors conclude that the shortcomings the decrease in gas temperature and the increase in the amount of solids in the extracted from the gas generator 10 Gas are essentially attributable to the fact that the granules 36 were not packed sufficiently tightly, when the granules were packed using the conventional so-called "tapping method". On the part of the inventor Carried out thorough studies of the behavior of the granules 36 in the cooling chamber 28 during a tapping process, including with the help of a high-speed film camera and a special housing made of a transparent material a movie was shot. It was observed that the individual granules 36 expand during the tapping process bounced more than expected in the cooling chamber 28 and that the granules were packed less tightly than expected. ■ If the granules 36 have an almost perfect spherical shape, as is the case with sand granules that are used for

609817/0766

Manufacture of sand molds used for metal casting, the tapping process is useful in order to achieve a sufficiently dense packing of the granules. Granules, however are used as heat-absorbing material in the gas generator 10 are too far from the spherical shape in terms of their shape removed in order to have comparatively large surfaces and to be effective in terms of heat and I increase particulate absorption. The granules 36 are usually in the shape of irregular polyhedra some curvature vertices. A tightest packing of granules designed in this way is achieved when a sharp-edged section of each grain is housed in one of the narrow spaces of the densely packed grains, where it is assumed that each granulate grain is in Plant is located with neighboring grains and with as large as possible surface areas. In reality it tends but every grain of granulate tends to jump out of the gap, what even then the. The case is when the granulate had already taken a position that closes would have resulted in a tightest packing. Without the theoretical considerations about the closest packing of non-spherical ones Wanting to deepen particles, it should be underlined that It has been found that heat absorbing granules 36 do not perform satisfactorily using conventional tapping techniques pack tightly.

Considerable high rates occur during the combustion of the pellets 32 Chamber pressures in the gas generator 10. In particular when the pellets 32 burn as intended in a very short time should, for example, within 0.05 seconds, for example To inflate a safety bag almost instantly in the event of a traffic accident, the pressure is in the

60981 7/0766

Chamber usually of the order of a few tens up to a few 100 kg / cm. The granules 36 loosely packed in the cooling chamber 28 become closed under such high pressures Causes movements. The movement of the granules 36 will caused by a "deformation of the Wire screens 38, 40 and the filter layer 42 supported. In addition, the reaction gas flows at high speed through the cavities between the granules, which supports a movement of the same in such a way that at least relatively further flow passage is formed in the granule layer. This has the consequence that at least part of the reaction gas without sufficient heat exchange with the granules and without sufficient absorption of solids on the Granules passes through the cooling chamber 28.

The strength of the movements of the granules and the manner in which the above-mentioned wide passage canal is formed are both influenced by the amount of contact between the wire shields 38 and 4-0 and the filter 4-2 with the neighboring bodies including the granules as well as the results of the tapping process. Because these factors in the mass production of the gas generator 10 vary within very wide limits, both the cooling capacity differ as well as the solids absorbency of the packed Granules are considerable in a large number of gas generators of the same type.

If the granules are subjected to vibrations and / or sudden shocks in a relatively loosely packed state, so the granules simply move and form one or more cavities between them. Are the vibrations and / or shock-like vibrations strong and / or long-lasting, the granules tend to be partial or local

609817/0766

by. Friction against each other to enlarge the cavities. The enlarged cavities make it easier for the granules to move further apart, so that the enlargement of the Cavities is progressively accelerated.

It can thus be seen that the conventional tapping method for introducing the heat absorbing granules 36 into the Gas generators 10 and 44 of the type described above have many causes for a relatively low cooling effect Granules and for a wide range in the operational characteristics.

According to the invention it has been found and confirmed by experiments that the above-mentioned disadvantages of the known tapping method can be almost completely eliminated, that a pressure load is applied to the granules 36 in the cooling chamber 28 such that a loosely packed Column or layer of granules solidified to some extent or is compressed. Neither the granules '36 nor the other components of the gas generator 10 or 44 require for Adaptation to the charging method according to the invention is a modification. The material for the granules 36 can be any known materials, such as the metals iron and aluminum already mentioned, or iron oxides, such as aluminum and magnesium oxides, and various other kinds of inorganic ones Compounds such as silicon carbide act.

The method according to the invention will first be explained with reference to S ¹ I. In the manufacture of the gas generator 10 according to FIG. 1, the partition wall 34, the udder 42 and the wire screens 38, 40 and 34 are initially or temporarily arranged in the housing 12. A subset of the heat-absorbing granules to be introduced into a single gas generator 10 is then poured into the cooling chamber 28. The housing 12 is then placed on a work table 60 of a press and becomes an annular one

609817/0766

Press ram 62 arranged on the column or layer of the filled granules. This ram 62 has a flat surface and an outer diameter slightly smaller than the inner diameter of the outer and cylindrical wire screen 40. The inner diameter of the ram 62 is slightly larger than the outer diameter of the inner wire network 38. on the ram 62 is a pressure force P ^ on the with the help of a press Granules layer 36 brought into action. The press, for example a hydraulic press, is provided with the reference symbol 64-. Then the ram is again lifted up.

The pressing leads to the compaction of the granules and an increase in the distance between the upper surface the granulate layer and the open end of the housing 12. Then a further subset of the intended total amount of granules is applied to the granules that have already been compacted filled and the pressing process repeated. These filling and pressing steps are repeated a few times until the The height of the compacted granule layer is approximately equal to the height of the partition wall 24. Then a cover plate 18 is on attached to the housing 12. An annular spacer (not shown) is placed between the compacted granules 36 and the cover plate 18 are provided, if there is an appreciable difference between the surface of the heat absorbing layer and the top of the partition 24 is present.

The compaction of the granules 36 according to the invention takes place in the gas generator 44 according to FIG. 2 essentially in FIG described way. As can be seen in Fig. 4, a suitable amount of granules is placed in the cooling chamber 28A of the device

60981 7/0766

Housing 12A filled after the partition wall 4-8 has been arranged together with the wire nets 52 and 54-. The housing 12A is then placed on the work table 60 and a support member 66 "is used which is inserted through the opening 22 in the housing 12A in order to prevent deformation and / or movement of the partition wall 4-8 during the subsequent pressing operations. A cylindrical , flat press ram 68 with a diameter which is slightly smaller than the diameter of the cylindrical cooling chamber 28A is applied to the granulate layer and with the aid of the hydraulic press 64 - according to S ¹ Ig. 3, a pressure load Pp is exerted via the press ram 68. The filling of granules and the pressing treatment are repeated a few times as already described with reference to Fig. 3. Subsequently, the wire screen 56 and the filter 58 are placed on the compacted granule layer according to Fig. 2 and the closure plate 18A is attached to the housing 12A.

The magnitude of the forces P ^ or Pp for "pressing" is determined taking into account the shape and breaking strength of the granules, the cross-sectional area and height of the layer to be compacted and the strength of the wire meshes 38, 40 (or 54-) and the filter 42 determined. a compressed by pressing granules layer exhibits an enhanced ability to absorb heat and which has been, however, packed using the conventional tapping method for receiving solids over a similar layer. the forces ¥ _Λ and P ₀ associated pressing pressure is in size

2 2

Order of 1000 g / cm, but at least 10 kg / cm are preferred to take full advantage of the inherent advantages of the invention. As the upper limit for the pressure 1000 kg / cm are preferred to prevent crushing of the granules.

609817/0766

If a compressive force is applied to one side of a layer made of a granular material, then in contrast to the compression of an ordinary medium, the force is not transmitted to the other side of the layer, as long as the layer thickness of this layer is sufficiently small compared to the layer width. When charging the Granules in the cooling chamber 28, it is undesirable to have a large amount of granules in the cooling chamber at one time 28 to fill in and a force on the resulting ddckere To bring the layer into effect. A lot of the one Granules to be used for individual gas generators are preferably divided into a few or more parts, which are preferably include equal amounts, and each sub-amount is compacted in the aforementioned manner by pressing before the following portion is filled. The number of subsets is determined taking into account the size and shape of the Granules and the ratio of height to width of the cooling chamber 28 is determined.

Eg are two ways to get the granule inserting point to determine. Firstly, it is possible to end the filling measures when the compacted layer of granules is a reached a predetermined height. On the other hand, however, it is also possible to end the filling measures when a predetermined amount of granules has been introduced into the cooling chamber 28, even if the height of the compacted Layer is then somewhat different for a plurality of gas generators 10. A uniform level of compacted Layer, as in the case of the route outlined first, in no way implies a uniformity of the amount of granules, as the dividing wall 34 - the mesh screens 38 and 40 with dimensional fluctuations which are inevitable in mass production.

609817/0766

Since the number of gas generating pellets 32 in a single gas generator iö very precisely controlled lead to fluctuations the amount of granules at different temperatures of the reaction gas emerging from the gas generator. on the other hand For example, fluctuations in the zero of the compacted layer can be compensated for by using, for example, a suitable spacer is used in the assembly of the closure plate 18. Accordingly, the second approach shown is also advantageous to be viewed, with particular emphasis on its superior adaptability to the respective operating conditions stands.

The charging process according to the invention has the following advantages over the conventional tapping process: First, the granules can be packed more densely. The effect of a compressive force on the loosely packed layer of granules leads to the fact that all furrows and spaces in the granules with a correspondingly shaped part of a single grain are filled and that the granulate grain filled or plugged up in this way does not come out of the furrow or the gap pops out. This has the consequence that a increased amount of granules in a cooling chamber 28 with fixed Volume can be introduced.

Second, even then, the granules 36 do not move easily when they are exposed to the reaction gas with pressures of quite a few 10 to several 100 kg / cm are exposed because the granules, the wire screens 38, 40 and the filter 42 are compressed together by the pressing process. The wire screens 38, 40 and the filter 42 are brought into close contact with the surrounding bodies and granules, even if they are initially when filling into the container 12 because of dimensional fluctuations in them and / or in the housing 12 not completely Were in contact with each other. As a result, the granules move

60981 7/0766

lien into a mass without breaking, even if they are forced to move to some extent under the action of the reaction gas. The condensed Wire nets or screens 38, 40 and the udder 42 exert restoring forces on the compacted granule layer 36, so that a movement of a single grain in the compacted Layer relative to the neighboring granules can hardly occur.

Because of the reduced mobility of the individual grains 36 in the cooling chamber 28, the reaction gas is prevented from stroke through the cooling chamber 28 and find only a slight resistance. As a result of the invention Charging process, the heat absorption and the absorption of solids take place in accordance with the construction underlying calculations. The ability to absorb heat and solids of the compacted Granules do not noticeably change even when the gas generator 10 is put into operation after numerous Has been exposed to vibrations and / or sudden shocks. This stability and uniformity in behavior of the compacted granules makes it unnecessary to use exact amounts of granules and, consequently, it is possible to to make the gas generator 10 smaller in its dimensions. The downsizing of the gas generator 10 is advantageous because it often together with certain devices in a very narrow space, for example inside the steering column of an automobile, is arranged.

The advantages resulting from compacting the granules can be increased even further by compacting the granules Granule layer after the completion, the filling work is left under a compressive force. Such permanent compression of the granule layer can be achieved by exercising then exerted a compressive force on the compacted layer.

60981 7/0766

be practiced when the closure plate 18 on the housing is attached.

During the production of the gas generator 4A according to FIG the shutter plate 18A together with the wire screen 56 and the filter layer 58 on the completely filled and "already compacted granules 36 applied as before described. Then the ram 68 is placed on the shutter plate 18A and becomes suitably strong Pressure applied to the ram 68 in the axial direction. The connection works, for example by Welding to produce a circumferential connection between the closure plate 18A and the housing 12A is carried out in such a way that the connection increased the load exerted on the cover plate 18A and above it also on the granules is. The same method of operation is applicable to the production of the gas generator according to FIG. 1 as long as the transmission the force exerted on the cover plate 18 on the granules is guaranteed. This can for example by using a suitable spacer or intermediate member between the closure plate 18 and the top surface the compacted granule layer take place. In this Case, the annular ram 62 is preferably used to transfer the load during the connection work on the To let the end plate 18 act.

A sustained compressive force thus applied eliminates any possibility of partial return of the tightly packed Granules in a loosely packed state during storage and / or during transport and holds the wire nets 38, 40 and the filter layer 42 in close contact with the neighboring bodies, i.e. the housing and / or the granulated layers. In addition, the above-mentioned reset

609817/0766

by virtue of the wire nets 38 and 40 and the filter sheet be increased and permanently effective. As a result, the uniformity and stability of the absorbency become for heat and solids of the granulate layer just as much increased, such as the resistance to vibrations and sudden shocks.

The invention is illustrated below by a number of examples explained in more detail.

example 1

A number of inflators of the type shown in Figure 1 have been manufactured. The inner surface of the perimeter wall 16 of the housing 12 was covered with a Fi It layer 4-2, which consisted of a glass fiber fleece, and then with a wire mesh 40 with openings of 0.4-2 mm. The ring-shaped Cooling chamber 28 was formed in that the tubular partition wall 24 is arranged coaxially in the center of the housing 12 became. The outer surface of the partition wall 24 was covered with the wire mesh 38, which had openings of 0.4-2 mm decreed. The inner surface was covered with a wire mesh 34- with an opening of 1.68 mm. The cooling chamber 28 possessed an outer diameter of 86 mm (inner diameter of the wire mesh 40) an inner diameter of 56 mm (outer diameter of the wire mesh 38) and a height of 57

As the heat absorbing material, alumina or Used clay. The alumina granules were irregular polyhedra with a major particle size of about 1 mm. The granules were first sieved and fines less than 0.71 mm in diameter were discarded The total weight of the alumina granules for each gas

609817/0766

2S4T724

Producer was set at 500 g and this amount was divided into four equal! EeilMemgea. A first amount of rope (125 ε) of the TcmerdegprainaXien was filled into the cooling chamber 28 and. With the help of a hydraulic press with a bridge of 80 kg / es, the tubular ram 52 had an outer diameter that was slightly smaller than the inner diameter of the outer wire netting 40 and the EreBsteaipel inner diameter of the Tarcliiaesser was slightly larger than the inner wire mesh 38 The same work steps were carried out with the remaining three alumina lettuce alumina lettuce * A ring-shaped five-tier dish was placed on the upper end of the jelly when the fourth aliquot was poured in and pressed, in order to avoid overflowing the granules Z11 still or slightly higher than the partition wall 2Pr. Then the circular cover plate 18 was arranged on the compacted layer of granules and joined to the housing 12 by welding, the weld seam being laid along the entire circumference of the cover plate 18.

'Then 150 g pellets J2 were aas a gas-generating In combination, the opening 22 into the combustion chamber 26 introduced. This gas generating composition or mixture "consisted essentially of a mixture aas Ealium perchlorate ubcL hatriuuazid. With the housing 12 was then the ignition device 20 was combined - this gas generator became operated at & maerbedbedingungen »so was the im

2 inside the housing 12 pressure formed about 60 kg / cm and the temperature of from dea housing 12 through the radial openings 1% abstroanendexi gas is about 180 ⁰ C. was The discharged together with the gas from dea gas generator 10 amount of solids about 0, 2 g.

609817/0766

Part of the gas generator manufactured in this example was subjected to a vibration test and another part to a drop test, each under the following conditions.

Vibration test: acceleration ± 4- G

Frequency 15 Hz

Duration 60 hours

Drop test: height 5 m

Soil type concrete

The experiment was repeated 10 χ.

Each of the respective trials was a number of the tested Gaserzexiger taken from each other to investigate whether changes the particle size of the granules. It turned out, however, that the granules got through very little Vibration or falling. The amount of fine granules with a particle size less than After the vibration test and the drop test, it was only 0.71 mm 2 or 1%, based on the total amount of alumina granules in the gas generators.

The operating characteristics of the gas generators after the vibration test and the drop test are summarized below.

After the vibration After the fall

2

Comb pressure: approx. 60 kg / cm approx. 60 kg / cm

Gas temperature: approx. 190 ^° C. approx. 180 ^° C. carried out

Solids: approx. 0.3 g approx. 0.3 g

609817/0766

These! Data show that the performance of the gas generator 10 could practically neither be affected by the vibration test nor by the drop test.

Comparative experiment 1

In the manner described "in Example 1", a variety produced by gas generators according to FIG. 1 with the exception that the alumina granules by means of the conventional tapping method were introduced into the cooling chamber 28. The same amount (500 g) of alumina granules was in five Tei3.volume divided and a tappiug process vrarde under Placement of the cover plate 18 on the open end of the housing 12 is carried out each time a proportion of the granules was filled into the cooling chamber. The operating characteristics of the gas generator 10 produced in this way are summarized below:

Chamber pressure: approx. 55 kg / cm

Temperature of

discharged gas: approx. 240 C

Amount of pesticides discharged: approx. 0.8 g

The decrease in chamber pressure and the increase in gas temperature as well as the amount of pesticides discharged the results obtained in Example 1 became relatively more and less involved as a result of training running channels for the gas flow in the loosely packed granule layer viewed. The gas generators were

60981 7/0766

sem comparison test the vibration test and the drop test Subjected under the same conditions as in Example 1 "reproduced. The following results were obtained:

Wake up to the vibration After the fall

Amount of granules with
Particle size of

less than 0.71 mm · 'about 15%

ρ Chamber pressure: about 50 kg / cm "

etvta. 5 % I. approximately 55 ρ
kg / cm " approximately 300 ⁰ C approximately 2, 5 p

Gas temperature: approx

Discharged

Solids: about 3.5 g

Example 2

This example also related to the manufacture of the gas generator 1 and the same alumina granules compressed by pressing in the cooling chamber, as explained in Example 1. The closure plate 18 was then opened the compacted layer was laid and the granules and the annular press ram 62 were placed on the closure plate 18. Hit the help of a hydraulic press was a pressure

of 80 kg / cm applied with the help of the ram in the axial direction and the welding work to connect the closure plate 18 with the housing 12 was carried out during the period during which said pressure by the ram was maintained. The experiment was carried out including the vibration test and the drop test in this example exactly the same as in example 1 and the following results were obtained:

60981 7/0766

Without vibration after, after the fall and drop tests vibration

Granules with
less than
0.71 now. Particle
size : approx. 60 ρ
kg / cm approx approx. 1% approx. 1 % kg / cm Chamber pressure: approx. 180 ⁰ C approx . 60 kg / cm ² approx. 60 ⁰ C Gas temperature: approx. 0.1 S. approx . 180 ⁰ C approx. 180 S. Solids content: - 0.1 g approx. 0.1

Example 3

This example relates to the production of a gas generator according to FIG. 2. Silicon carbide granules were used as the heat-absorbing material used in the form of irregular polyhedra with an average particle size of about 1 mm. These granules did not fall through a sieve with a mesh size of 0.71 mm. The wire nets 52 and 54-> which cover the partition wall 4-8, consisted of that in Example 1 explained material. The total amount of silicon carbide granules for each inflator 44 was 500 g and was divided into four equal subsets. Each granule subset was filled into the cooling chamber 28A, which has a diameter of 82 mm and a height of 43 mm. Then a hydraulic one Pressure of 100 kg / cm applied, the cylindrical ram 64 had a diameter that is slightly smaller than the diameter of the cooling chamber was 28A. During the pressing, the partition wall 4-8 was held by the support member 66. After this The fourth granule aliquot had been compressed, the wire mesh spacer 56, which was made from the same material existed, like the other wire nets 52 and 5 ^ -, cleir filter 58 made of solid felt and the closure plate 18A placed on the compacted granule layer 36 in the order mentioned. So-

60981 7/0768

then the ram 68 was applied to the shutter plate 18A and a pressure of 100 kg / cm was transmitted via the ram in the axial direction. The locking plate 18A was connected to the housing 12A by a weld seam along the entire circumference, wherein during the Welding the pressure was maintained with the aid of the punch 68. The gas generating pellets 32 and the Ignition device 20 were of the same type as in Example 1. The test procedure and the vibration and Drop tests were carried out in the same manner as the previous tests with the following results became:

Without vibration After the After the EaIl and vibration drop tests

SiC granules
with particle size less than 0.71
mm: - approx. 1% approx. 1 %

Chamber pressure: about 90 kg / cm 90 kg / cm 90 kg / cm ¹ "gas temperature: about 200 ⁰ C ⁰ C ca.21O about 200 ° C

Solids content: approx. 0.2 g approx. 0.2 g approx. 0.2 g

Comparative experiment 2

Example 3 was repeated with the difference that the silicon carbide granules were tapped using the conventional tapping method were inserted into the cooling chamber 28. The total amount of granules was divided into five sub-amounts and the shutter plate 18A was integrated with the housing 12 without applying any stress to the plate. The measurement results are summarized below:

6098 17/0766

Without vibration After the tray the pail and drop tests vibration

SiC granules - with particles approx. 80 kg / cm size of we approx. 260 ⁰ C less than 0.71 mm: approx. 1.5k Chamber pressure: Gas temperature: Solids volume stop:

approx. 2% approx. 5 %

2

approx. 70 kg / cm approx. 80 kg / cm approx. 400 ⁰ C approx. 320 ° C

approx. 5 g approx. 2.5 S

60981 7/0766.

Claims (1)

Claims A method for manufacturing a gas generator having a a chemical contained in a housing, which is able to form a hot gaseous reaction product, and a granular heat absorbing material to reduce the temperature of the reaction gas before it is discharged, characterized in that a) the granular heat-absorbing material is filled into a chamber provided in the housing in such a way that that the granular material in the chamber forms a loose layer with only one exposed surface and that b) a compressive force is applied to the free surface of the layer in such a way that the force is substantially is distributed over the entire area of that free surface and the grains are compacted in the process. Method according to claim 1, characterized in that that the force is applied with the help of a flat ram pressing on the free surface of the layer will, v / obei the shape of the flat end face of the ram corresponds to the free surface, however, is slightly smaller in size than the free surface. 3. The method according to claim 1 or 2, characterized in that that the total amount of the in the chamber 60981 7/0766 to be introduced granular heat-absorbing material before carrying out process step a) in a A plurality of subsets is subdivided, and that process steps a) and b) with each of these subsets are executed. 4-. Method according to claim 3, characterized in that that the subsets each comprise corresponding amounts. 5. The method according to any one of claims 1 "to 4, characterized gekennz eichnet that the magnitude of the force is determined in such a way that a pressure im on the layer Range of 10 to 1000 kg / cm is exercised. 6. The method according to any one of claims 1 to 5, characterized eichn et that following the Process step b) a cap is placed on the free surface that a cap on the cap Pressure force is brought into action in the same direction as when the force is exerted in process step b) and that the closure cover is attached to the housing is while the application of the compressive force on the cap is maintained. 7- method according to claim 6, characterized in that that between process step b) and the placement of the closure cover at least one layer of one resilient material placed on the free surface will. 8. The method according to any one of claims 1 to 7 _5, characterized in that the chamber and the layer 60981 7/0766 in a cut parallel to the free surface have an annular shape and that the chamber and the layer are arranged such that the gaseous reaction products from the inner periphery to the outer periphery flow through the layer. 9- The method according to any one of claims 1 to 8, characterized characterized in that the chamber and the layer are designed and arranged such that the Gaseous reaction products flow through the layer from one opposite to the free surface Surface to the free surface. 10. The method according to em of claims 1 to 9, characterized characterized in that the grains of the heat absorbing material have the shape of irregular polyhedra own. 11. The method according to claim 10, characterized in that that granules of aluminum oxide are used as the heat-absorbing material. 12. The method according to claim 10, characterized in that that granules of silicon carbide are used as heat-absorbing material. 609817/0766