DE1942207A1 - Timer charge - Google Patents

Description

19th August 1969 Thatcher 9

E. I. DU POSHD DE BEMOUHS AHD GOMPAHY 10th and Market Streets, Wilmington, Delaware 19 896, T.St.A.

Timer charge

The invention relates to improvements in explosive time fuses and relates more particularly to a new delay fuel for such time detonators. .

Time detonators are known and usually have the lorm of Detonators, which apart from the usual initial charge (the usually consists of a basic charge and an initial charge) and an ignition charge contain a delay charge, the is located between the ignition charge and the initial charge »These time detonators are intended for a specific point in time after the ignition of the squib to detonate, and this point in time (the delay) depends on the characteristic Properties of the delay charge. Time detonators are usually used in delayed detonation to ensure that a series of explosive charges are placed in a specific order, often at carefully calculated intervals of the order of magnitude of a few milliseconds, fired by only one application of an electric current to the explosive device will.

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In current technical practice in the United ^ States of America contain electric time detonators with relatively short delay times, for example in the Magnitude of 25 or up to 50 milliseconds or more, a retardation fuel that has been pressed and enclosed in a metal capsule, and also a separate one Initial charge, as it is, for example, in the German Pat. "Very. 9 * 1 473

is described »which refers to a lag race & ub amorphous boron and red lead. Although mixtures of boron and red lead can be used for both initial charges and delay charges, they must be in the form of separate charges in various states, namely compressed and preferably enclosed for use as a delay charge, and loose and unpressed, and for use as an initial charge the most favorable proportions of the two constituents are not necessarily the same for the two charges. Furthermore, as far as is known, loose (ie unpressed) delay charges have not yet been used in customary technical practice.

The invention relates to an explosives - »time fuse that at least contains an initial charge and a delay charge and is characterized in that the delay fuel of the delay charge is a metal salt of trinitrotoluene. The invention also relates to a method of assembling such a timer and to the use of one such a metal salt of trinitrotoluene as a retarded fuel.

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Preferred salts are the sodium, potassium and lead salts? it but other metal cations can also be used, especially those of others. Alkali metals, those of the alkaline earth metals, like barium, also aluminum, iron, copper and silver. At least some of these trinitrotoluene salts are already has been proposed for other uses in explosives, e.g. Obtains fuels containing metal salts of trinitrotoluene for use as smoke generating compositions. It can Mixtures of salts are also used and are beneficial, to achieve the desired delay with the required level of security.

The salts can be produced according to normal processes » The mono- and disubstituted alkali salts and the alkaline earth salts can by reacting trinitrotoluene with a Hydroxide or alcoholate of the metal in question e.g. trinitrotoluene is dissolved in methanol and mixed with an equimolecular amount of sodium methylate in the form of a ' 25 percent solution reacted in methanol, which becomes methanol evaporated and the residue slurried in benzene do that to remove unreacted trinitrotoluene and the monosodium sala to win. The heavy metal salts can be obtained by double reaction of an alkali salt with a water-soluble one Heavy metal salt, such as a hiteate, sulfate, chloride or acetate, getting produced.

For economic reasons and security considerations and for The srinitrotoluene is preferably used with a conventional one for easier control of the burning rate of the charge Burn rate modifier such as that in the German Pat.-Sehr, i 115 628 mentioned sweibasic lead phosphite, in amounts of 1 to 20 weight parts per part by weight

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Mixed trinitrotoluene salt. Mixtures to 20 to 30 Ge. weight percent from the sodium salt of trinitrotoluene and to Rest of dibasic! Lead phosphite are particularly valuable. Instead of dibasic lead phosphite one can use as Modifiers for the burning rate also oxidizing agents, such as oxygenates, e.g. sodium or potassium chloride, Potassium perchlorate or other perchlorates, potassium aermanganate or other permanganates, barium peroxide or other peroxides, citrates such as ammonium or sodium nitrate, or mixtures thereof use.

The remainder of the timer can be conventional. The initial charge can contain a basic charge of the usual type, for example pentaerythritol tetranitrate, gyelotrimethylene trinitramine, picric acid, trinitrotoluene and / or tetranitro-B-methylaniline, and an initial charge that is even more sensitive to flames or impacts, such as lead azide or mercury:? On the other hand, it is generally not necessary that the time fuses according to the invention contain a special ignition charge, because the trinitrotoluene salt not only acts as a delay charge, but is generally so sensitive that it also acts as an ignition charge. In this respect, the time detonators according to the invention differ from the conventional time detonators with separate ignition and delay charges _{or the like}

To further explain the invention, reference is made to the drawings Referring to the time fuse according to the invention in section represent.

Fig. 1 shows an electric detonator which has a tubular Has jacket 1 with a rounded, one-piece bottom, into which first a base charge 2 and then an initial charge 3 is poured. The delay charge 4 is looker heaped up, and is of the rubber stopper 5 in the jacket 1

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held. In the plug 5 insulated wires 6 are arranged, which extend into the delay charge 4 and are connected there by a bridging wire 7 of high resistance are. The plug 5 is in the jacket 1 through the circumferential constrictions 8 of the jacket 1 held.

Fig. 2 shows a similar timer that is used for actuation is determined by a burner, so that the components 5, 6 and 7 are not required and the capsule by the burner 9 is ignited, which acts on the delay charge 4 and is held in place by the constrictions 8 will"

The time detonators can be assembled according to conventional methods as described in the examples below and otherwise correspond to the known design with the exception that the delay mass according to the invention can be filled in as a loose solid powder and in contrast to the hitherto known delay mixtures of boron and red lead require neither compaction nor inclusion »It is advisable to to use normal procedures, e.g. to remove the wad 5 (as shown in Fig. 1) always to be attached in such a way that it has the same degree of compression in every time fuse of any type exerts on the delay mass, leaving any unnecessary cause for a possible fluctuation in the delay time is avoided.

It is significant compared to the time fuses known to date Advantage that a special delay charge can be omitted. The detonator and the retarder fuel also have a better resistance to electrostatic charges than e.g. retardation compounds Boron and red lead. The shelf life of the new delay charges is excellent what emerges from the close-

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Table III gives «. The fact that the retardation mass can be in a loose condition offers one Advantage in the manufacture of the time fuse, since the pre-pressing delay charging can be dispensed with. It is to be expected that this time fuse will prove to be advantageous in technical practice prove, especially for short delay times of the order of 25 or 50 milliseconds.

In the following examples, parts, proportions and percentages relate to, unless otherwise stated the weight"

B e 1 s pi e 1 '1

Several electric detonators are made, as in Pig. 1 shown, assembled. The bronze jacket 1 is 2.9 cm long, has an outside diameter of 6.9 mm and an average clearness Width of 6.6 mm. The basic charge 2 consists of 0.35 g of pentaerythritol tetrani and is taken with a sharp pencil pressed at a pressure of 100 to 110 kg. The initial charge 3 Consists of 0.15 g of lead azide and is used with a blunt pen pressed under a pressure of 90 kg "The delay charge 4 the composition given in the table below is left in a loose state, i.e. not pressed Samples E, F and G are the trinitrotoluene salt in the specified proportions with a also in finely divided Form present modifier mixed. The rubber stopper 5 is insulated with iron wires 6 of 0.65 mm in diameter and 2.5 aj length provided by a soldered bridging wire 7 of 3 mm long, 0.04 mm in diameter and one electric Resistance of about 1 ohm connected together, the in the loose delay charge 4 is embedded »The plug 5 is firmly seated in the three circumferential fittings 8 of the jacket 1. These capsules are supplied individually by an electric

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Current of 5 A fired, and the delays observed in the process are given in Table I; they are from the moment the electric current is switched on until the moment the detonation of the base charge measured.

- ΤΟ 0 9 8 1 6/12 2 5

• ■ sample Trinitrotoluene salt T a belle I Delay; A. N / A Charge
amount, g number of
fired
th capsules Mean value B. K 0.28 5 15.4 C. Cu (OH) 0.28 5 3.6 D. Ag (OH) 0.21 10 8.24 E. 90 i> Pb-10 # KClO ₅ 0.21 10 13.6 I. F. 20 i> K-80 # BaO ₂ 0.21 10 3.5 00
8th S. 20 i » Na-80 # BaO ₂ 0.42 ■ 5 16.5 H Pe (OH) 0.42 5 15.6 . ι ■; ■ '. ■ Al (OH) 0.35 5 16.8 0.25 ; , '■ * ■' ■■ 30.0 ο
co
co σ> ro
Κ »
«Ή

I am ready

14.5-16.5 3.2-4.1 7.8-9.0

12.8-14.1 3.2-4.1

14.8-18.3

13.0-17.6

16.3-17.5 26.8-31.6

CD -tS K) K) CD

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If five capsules, similar to sample A, with one amperage are fired by 1 A, the mean delay is 33.1 milliseconds and the delay range 31.4 to 35.1

Milliseconds.

B e is ρ i el 2

A delay mixture of 30 parts of the sodium salt of trinitrotoluene and 70 parts of dibasic lead phosphite is produced by mechanical mixing of the finely divided components in a mixer, agglomeration with a binder mixture of equal parts of triehlorethane and a liquid polyfunctional mercaptan (available under the trade name "Thiokol I» P-2 ^M ), Sifting through a sieve with a mesh size of 0.6 mm and drying for 24 hours at about 30 ° 0.

This delay mass is given in Table II Amounts used as delay charge in time detonators which are essentially similar to those of Example 1, with the difference that that the jacket 1 is 3 cm long, the initial charge 3 is applied in an amount of 0.21 g, and the test after a multiple firing process takes place. Be with every attempt five capsules, each with the same amount of delay charge included, connected in series to a conventional blasting machine, the blasting machine is discharged, and the longest delay, i.e. the delay from the point in time switching on the electric current until detonation the last of the five basic charges is determined. Four such attempts will use 20 capsules, all the same amount Delay charge included, investigated; the longest mean delay time and the range of longest delay times for the four trials are recorded and given in Table II. This procedure is used to examine

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five different amounts of delay charge, in total

that is, applied to 100 time detonators.

XaVeIl e II

Longest delay time, Milliseconds ! amount of charge, g Average area 0.14 7.0 3.4 0.21 12.4 1.6 0.28 13.2 1.4 0.42 17.2 1.9 0.46 18.6

Similar time fuses containing 0.335 g of the mixture are stored under the specified conditions and then fired individually in water at 25 ° 0 with a blasting machine, giving the results compiled in Table III _o

! Table III

Storage conditions (number of months)

atmospheric (1) 3B ⁰ G ₉ 85 # relative humidity

(O (7)

atmospheric 38 ⁰ C, 85 i » relative humidity (7) 70 ° 0 (15) atmospheric (16) atmospheric (24)

number of

examined

Time fuse

5 5

5 5 4 5

Third delay time.,

Milliseconds
Mean range

8.4

8.9
9.3

14.5
20.4
10.3
11.8

4.8

3.4 2.5

2.1 7.1 2.0 8.1

The atmosphere of 85 5 * relative humidity is by means of a saturated aauonium eulfate solution in a closed container

ter in an oven

C generated.

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These results show the surprising consistency below normal storage conditions and sufficient stability even under unfavorable or unusual conditions.

It is therefore to be expected that such time fuses will prove to be valuable in technical practice, especially for relative purposes short delay times of up to 50 milliseconds. Longer delay times can be achieved by using the Quantities in the delay charge vary as it does is given in Table IV. This table shows the results, which are obtained when using similar time detonators, the 0.46 g of similarly manufactured delay masses of the specified Composition included, fired individually under comparable conditions.

Table IV

number of
Time fuse Delay Time,
Milliseconds fluctuation 12th Average 2.6 12th 91.5 2.4 40 76.0 1.8 12th 32.3 0.3 ί5 26.9 1.3 B e i s ρ i e 11.1 1 3

Ratio trinitro

toluene salt: dibasic

lead phosphite

10:90 15:85 20:80 25:75 30:70

Similar time detonators, each 0.385 g of a delay mixture from 10 parts of the sodium salt of trinitrotoluene, 45 parts of dibasic lead phosphite and 45 parts of potassium chlorate or potassium permanganate result in average delay pages of 10.4 milliseconds (with a fluctuation of 5.1 milliseconds) or 45.4 milliseconds (with a fluctuation of 13.5 milliseconds) in a series of ten attempts. Twenty similar

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Time detonators »the one delay charge iron each 0.45 g one Mixture of 20 parts of sodium salt of trinitrotoluos, 40 parts of dibasic lead phosphite and 40 parts of barium peroxide contain / result in a mean delay time of 24.1 milliseconds (with a variation of 6.2 milliseconds).

Example 4

^ Detonators actuated by fire detonators of the type shown in Figo 2 are assembled according to Example 2, with the Difference that the bronze jacket is 1 6.25 cm long and the Delay charge consists of 3.5 g of the potassium salt of trinitrotoluos and presses it with a flat-ended pen of 90 kg is pressed ο the electric ignition system is replaced by a short, uniform length of a low-energy fuses with a nuclear charge of 0.002 g of pentaerythritol tetrani a cm. If ten such capsules fired individually, an average delay time is obtained of 2.3 seconds with a delay range of 2.24 to 2.49 seconds.

j Comparable results are obtained with capsules which are ignited with the aid of burners and which contain larger delay charges, which in some cases are additionally compressed.

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Claims (3)

Patent claims Use of a metal salt of trinitrotoluene as a timer charge 2. Explosives time fuse »consisting of a tubular Dumbbell »an initial charge and a delay charge» the electrical initial ignition or initial ignition by means of a detonation fuse, either directly or on the Paths via an initial charge »responded» characterized »that the delay charge consists of a metal salt of trinitrotoluene. 3. Time fuse according to claim 2, characterized in »that the Metal salt of! Trinitrotoluene mixed with a modifier for the burning rate, such as the form of lead phosphite which is "present" -13 - 009816/1221 Blank page