US1878652A - Process of initial detonating explosive matter and for the manufacture of detonating caps in accordance therewith - Google Patents

Description

- explosives such Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE.

EDMUND VON HER Z, OF COLOGNE-DELLIBBUCK, NEAR COLOGNE-ON-THE-BHINE,

. GERMANY PROCESS OF INITIAL DETONATING EXPLOSIVE MATTER AND FOR THE MANUFAC- TUBE OF DETONATING CAPS IN ACCORDANCE THEREWITE No Drawing. Application filed October 22, 1929, Serial No. 401,609, and in Germany can... 16. 1928.

All the detonating caps as hitherto used are constructed with regard to the effectiveness of the so-called priming or initial explosive matter, i. e. such explosive which even in smallest quantities will be Completely detonated by ignition, by a these initial explosives, the most important representatives of which are the fulminates and metal azides, cause much inconvenience by reason of being so sensitive against blow and friction which makes the manufacture and handling of these materials very dangerous.

For this reason proposals have been continually made, the aim of which being to substitute these dangerous materials by explosives or priming compositions which are less sensitive. Most of these proposals were made at the time when dynamite was predominant and their object has been exclusively the detonating of nitroglycerine explosives because it appeared hopeless to detonate as ammonium nitrate explosives and aromatic nitro compounds, the ignition of. which is diflicult and can be accomplished only by means of initial explosives. These proposals concern in most cases quick burning or fulminating compounds of potassium chlorates, and such compounds with metal sulfides, metal rhodanides, salts of persulfocyanic acid, picrates etc. and thermite compounds. But the ignition eifect of all these compounds is so feeble that even the sensitive giant powder No. 1 will not be detonated with certainty and if ever, only a part of its energy is effective and in some cases the gelatinized dynamites only will give feeble explosions. It was therefore impossible to carry these proposals into practice.

The object of my present invention is based upon the surprising discovery that in contradistinction to nitroglycerine the solid nitric acid esters, which are combined according to same formula C M- (NO,,) as per ex ample tetranitroerythrite, hexamtrosorblte, hexanitromannite etc. even in very small quantities are completely detonated by an 1ntense flame tongue. This fact, hitherto unknown, is of highest importance because upon it only by combination of such a nitric acid flame or spark. But p ester as an intermediate detonating charge with a suitable ignition material, detonating caps may be constructed, which will detonate with full effect not only dynamites but also the most insensitive ammonium nitrate exlosives. Thereby they become equivalent to the best detonating caps with initial explosive. The advantage of this new type of detonating cap is evident. These nitric acid esters being far more insensitive than the common initial explosives such as fulminate of mercury .for lead azide it is possible to produce ignition materials of complete insensitiveness so that the manufacture and the handling of these detonating caps is very much safer than that ofthe common initial blasting caps and they can be considered as practically harmless. The manufacture is very much simplified because instead of very complicated plants for the manufacture of the initial explosives only a small mixin plant for the ignition material is require Further the complete insensitiveness of these detonating caps against moisture and their durability during storage is to be pointed out. These latter qualities make these new detonating caps especially suitable for shell and mining detonators and for other military purposes.

The chief method of construction of these detonating caps is that any quantity of a.v

nitric acid ester is loaded into a common detonating composition tube and on the top of it is pressed a small quantity of ignition material. It is advisable to cover the nitric acid ester charge with one of the common perforated inner caps and to press upon this cap the ignition mass.

Out of the numerous nitric acid esters which are to be considered the nitromannite is the most suitable and chiefly to be recommended on account of its low price and because it is easy to be supplied. Very excellent results are obtained by mixing nitromannite and nitropentaerythrite in their molecular proportion which will give a complete combustion and in consequence the force of explosion will attain its maximum effect.

As regards the ignition material one has a greater choice because nearly all fast burning compositions giving a hot flame tongue are suitable. Several practical causes confine this ambit a little, because the mass is to be insensitive as much as possible against blow and friction. On this account the chlorate compounds which otherwise would work well must be eliminated and also unpowder and thermite, because in a pressef state they burn too slowly and ignite precario usly. On the other hand those sets containing magnesium and aluminium such as are used in the pyrotechnics and in light-balls have turned out well after corresponding alterations had been made. These are compounds of magnesium and aluminium powders with oxygen carriers such as nitrates, perchlorates, permanganates, chromates or superoxides and if necessary with other combustible materials. One example of a. composition especially suitable for the present purpose is: 'Per cent Bariumnitrate 58 Magnesium powder 29 Lead hypophosphite 13 The lead hypophosphite as well as all other oxygen carriers and lead hypop layer being separated from the main charge inflammability and they serve this purpose better than all other materials.

Example for a detomting cap 2V 0. 8

In a detonating cap tube No. 8 0.5 gr. nitromannite are loaded or the same quantity of a molecular composition with nitropentaerythrite and pressed after covering it with a perforated inner cap with a pressure of 100-400 kg. upon a cm. Then 0.15-0.3 gr. of the above named priming or ignition mass are placed on the top of it and the same pressure is exercised once more. The efiect of this new detonating cap is almost tBlTm same as that of a first class detonating cap What I claim as new and desire to secure by United States Letters Patent is:

1. A detonator containing a main charge of nitro-mannite and a superposed layer comprising a metal selected from the group consisting of aluminum and ma esium with osphite, this by the usual perforated inner cap.

2. A detonator containing a main charge of nitro-mannite-nitro-pentaerythrite mixture and a superposed layer comprising a metal selected from the group consisting of aluminum and magnesium with oxygen carriers and lead hypophosphite, this layer be ing separated from the main charge by the usual erforated inner ca 3. ii detonator containing a main charge of a solid nitric acid ester of the general type (J,,H,,, .(l TO and a of a powder mixture of high thermical effect, comprising a metal selected from the superposed layer 7 group consisting of aluminiumand magnesium with oxygen carriers and the inflammlability increasing substance lead hypophosp its.

4. A detonator containing a main charge of nitro-mannite and a superposed layer of a powder mixture of high thermical effect, comprising a metal selected from the group conslsting of aluminium and magnesium with oxygen carriers and the inflammability increasing substance lead hypophosphite.

5. A detonator containing a main charge of a nitromannite-nitropentaerythrite mixture and a superposed layer of a powder mixture of high thermical efi'ect, comprising a metal selected from the group consisting of aluminium and magnesium with oxygen carriers and the inflammability increasing substance lead hypophosphite.

In testimony whereof I have afixed my signature.

EDMUND voN HERZ.